Yesterday it became official: Fate is a bitch with a cruel sense of humour and I am the mother of a child with autism.

 The crazy part is that though I'd been working for three years to secure a diagnosis for him; though I understood exactly what kinds of support it would finally make available to us; though it settles instantly the question of whether he stays in his current, difficult, mainstream school or not, when it finally began to settle in, it left me devastated.

 Families of other autistic children that I'd met during the course of my struggle had warned me that while the formal diagnosis - when it eventually comes - is everything you've been hoping for, it will still hit you like a train. I figured they were overstating for drama's sake. But they were utterly and completely correct and now I understand exactly what they meant.

 The diagnosis was delivered right at the start of a three-hour wall of meetings that began at around 10am. The meeting schedule left me no time digest, consider and react to its deliverance at all. Worse, its existence was a key factor in the following meetings so I was raising it in pragmatic, cerebral terms and talking about its implications for hours before I was able to just pause, breathe and feel about it. Finally when the meetings ended some fifteen minutes before I was due to collect my son from school for the day, I went for a "Wow, that sucked," cigarette and was suddenly bowled over.

"Bowled" is not a good word for what happened. But I can't think of a better one and bowled might, perhaps, conjure up an image of a hard, fast cricket ball destroying a set of wickets.

 I've never experienced anything like it; a physical force hitting me hard in the stomach would have felt no different. I lit my smoke, took a breath and, BAM! I was doubled over and struggling to absorb the news that had been delivered - now I look back at yesterday - with obviously shitty timing. For a while it was a struggle to breathe, even. It was all pure reaction - no emotion, no tears, just the shock of the diagnosis hitting me with a physical force.

 But worse than the unexpected doubling over; worse than the having had to wait three hours before being able to react at all was the very first thought that went through my mind when I - at last - was able to begin framing the diagnosis within a personal context: It wasn't me; I didn't do this to him.

I didn't realise - had absolutely no idea - that I'd been carrying around with me some kind of guilt about having been such a bad mother that I had, somehow, disabled my child. And for all this time? I look back 24 hours to that moment and my heart breaks a little that anyone (let alone stoic, "Let's get this over with" old me) could have ever entertainedsuch a sad, heavy thought.

It's been a hard twenty-four hours and the emotions still aren't making any sense: Where's the satisfaction and triumph at having stuck to my opinion and not yielded when so many "professionals" tried to dismiss my worries? Where's my sense of personal vindication for the many, many decisions I've made that go right back to when he was tiny that were based upon my gut instinct telling me that he simply couldn't do whatever it was?(My refusal to attend mother and baby groups remained - until yesterday - a contraversial issue that was still regularly doing the rounds at meetings and assessments) Where's the optimism that comes from knowing that, finally, his needs are defined and recognised in such a certain, undeniable fashion? And what about the simple relief at finally being able to approach support groups and family networks and get some help?

Nope. None of that is factoring in at all; my son is autistic ("Placed upon the spectrum by a significant margin with enough evidence at this age to prompt further Asperger's Syndrome-specific enquiries later on.") and I nailed it so completely so long ago... and I so badly wanted to be crazy. It took me a long time to be able to use the word "disabled", and I suddenly hate the phrase and everyone to whom it's an alien concept that happens to other people.

Comfort is a cold thing when you're a parent facing something like this: the grief is deep, pronounced and constant and with it comes a huge wave of guilt that you can feel so much loss about a child that you love so completely and who causes you so much joy and pride on a daily basis. And the juxtaposition is raw and ugly, like the earth after a quake has hit. It's an unfair (and, in many ways, cruel) balance to have to strike, frankly; his medical definition breaks my heart though he's no different to how he was yesterday or the day before or the day before that.

In a way, I guess, I'm grieving for myself and for those sweet maternal dreams we women make when pregnancy hits the third trimester and we start to fantasise about our future lives with our children. I didn't have big plans for Euan - his life is his own and I only get to hold his hand until he's ready to do it alone - but to have so many of those automatic preconceptions that I imagined so easily rendered irrelevant is difficult to accept.

Of course, there's the old "It's only autism" chestnut that I've been using whenever anyone expresses even the slightest degree of sympathy for my son and I. And that does hold some truth: there are parents who are facing disabilities so much more pronouced, fundamental and serious than Euan's that I feel almost selfish to be indulging myself over something relatively trivial.

But, unlike with many of the more serious childhood diagnoses, there's no real "But..." to it. Seriously life-threaning disorders can bring inherent comfort at the fact that the child is still alive at all; other conditions and diseases can be managed or treated all together and there's something concrete that parents can do to feel that they're contributing in some way to their child's welfeare: autism builds a bubble around a child that even parents can struggle to penetrate at times, which makes trying to be proactive seem often futile. And always with other childhood issues, the bond between mother and child remains untouchable - with Euan and I, it's always been at stake

 Autism is insidious: It lacks both definition and limitations. And while it's making a fairly obvious future-genius of my son, it's also steadily robbing him of his childhood and his emotional connections with other people. For example, he has never once cried when I've left him somewhere. Attachment separation just doesn't exist for him at all.

So, I'm thinking, I can try to be stoic and brave and so very British about all of this, and refuse to admit how deeply this has struck me - in spite of all the time I've had to watch it approach - or I can acknowledge how I feel and react accordingly; nurse my broken heart, deal with my emotional reality, find a way to settle that cruel  dilemma.

Because the sad fact is that out of my son and I, I'm the only one currently capable of doing that at all.