My oldest ds, now 8.5, is my only fully vaccinated child (I even did the 5 year boosters, pregnant, depressed and under pressure as I was, which I now totally regret). I picked this particular thread because I think when ds was about 4 I could no longer ignore the feeling (or the obvious if you will) that my child was "different" in ways I couldn't put my finger down on.
I'll try to make this short, though I have to say honestly that I have no official dx for my son, nor do I have solid proof or even a solid memory about what vax may have triggered what, and so on. Ds, Kieran, also may have been inflicted by low levels of oxygen during and after birth (about 36 hours of poor blood ox levels), routine use of abx in the NICU (no sign of infection whatsoever) before he even got to have any breastmilk, and was in such rough shape from pulmonary hypotension and collapsed lung that he spent several days just clinging to life before starting to recover. Kieran's sensory issues could be related to his NICU stay, however, he did not have these issues as a baby. Aside and despite the rough start, he was a happy, healthy, easygoing baby who was breastfed (until 16 mos), at least. Despite his birth, for the first year, he was quite healthy, and hit all the milestones with no problem.
When he was a toddler, it was like a storm hit the house, but we had nothing to compare it to, and just thought this was normal toddler stuff. What parent won't say their kids will start a tantrum at the drop of a hat? Not many IME lol. I grew quite protective over him when critisized for his lack of speech for his age, saying, his father didn't say a word until he was 3, some kids develop later than others, I'm not going to pressure him and make it worse. I went with my gut, and in the end, don't regret not seeking out speech therapy.

: I remember we just stopped listening to music much of the time, because it seemed to cause Kieran actual physical pain. The musician part of me was sad and hurt and confused, simply wanting to pass on the love for music, and the mama part of me was just baffled. I'd never seen anyone behave like that before over not-loud music. Now, it doesn't seem to bother him.
By the time he was four, only Dh and I could understand his speech for the most part. And interacting with him was hard sometimes, like getting his attention (his hearing is fine btw) , especially when trying to explain something simple to him and he would not get it, it would not sink in. For example, we went through this phase where he was constantly trying to escape the house in the wee hours of the morning to run down the block to the local milk factory b/c there was a store front there w/ stuffed animals and ice cream available. He managed to get all the way there a handful of times (barefoot and in jammies of course) and it was so bad the police were involved and ready to call CPS. (yes we got the locks for the doors and everything). Me, Dh and the nicer police officers constantly tried to deliver the same simple message "Do not leave the house without mommy or daddy". It never sunk in the whole time we lived there, and I still get shudders thinking about the anxiety that put us through until he finally seemed to stop trying to take off.
Fast forward to today, he speaks just fine (starting at about 5), although I believe he has an auditory processing disorder (why he doesn't hear me sometimes, and I also believe I have the same thing) which explains the "I can hear but I can't" thing. I've basically just learned to work around it, keeping in mind that I will not treat him the way I was treated for it (called a space case, always getting yelled at for not "hearing", I did not grow up in a great home anyways).
He's very quirky, very sensitive (high empathy, though his going off the deep end over little things really wears on me sometimes), and extremely smart. I highly suspect he is somewhere on the AS, but I'm not actively seeking a dx at this time, because honestly, we've been doing pretty well without it, especially now that he is older and over the speech delay. I'm also just tired of dealing with the medical field in general as it usually brings us
nothing but emotional and physical distress and invasion/harm. If there comes a time I feel a dx would actually help, I'm always open to seeking it out if I have to cross that bridge. I've spent the past few years just learning to accept that Kieran is Kieran.