i can somewhat relate to how you're feeling. we were having nothing but problems with our son when he was little, he is ten now. he almost got kicked out of elementary school in second grade. at home he did things like punch holes in the wall. eventually we had him evaluated, and he was diagnosed as bipolar and is now on medication. it took me a long time to get over the guilt and fear and mental exhaustion. he is doing much better now, with the meds. especially since we switched pdocs and he was also diagnosed with adhd.
i don't know a whole lot about autism, but for me, just the thought of something being wrong with my son, my baby, was unbearable. and i felt so guilty, because most likely i gave it to him.
and my little guy, who is four now, has a heart defect. he is going to have heart surgery this year to fix it.

it must be extra hard for you, being pregnant, hormones all over the place, being extra weepy and emotional as is. can you talk to your husband? is he supportive? do you have a decent support system? how about a mom's group?

i'm sorry, i'm probably no help at all.

I do hope things will get a bit better for you, and that you will be able to calm down some.