I wouldn't usually say this because I'm very much a devoted non-church goer. But for a single mom struggling to raise a socially challenged child you might consider visiting local churches until you find ones that wants to help you. There will be old folks and young teens with the patience to include your child and parents who feel like they should be supportive of your emotional needs. I hate to think you're suffering trying to be strong.
As for the gifted part, regardless of any kind of testing or scores, if your son is interested in math and science what's the harm in letting those be his interests? Consider buying toys that remind you of these for his Christmas or birthdays:
http://www.mathartfun.com/shopsite_sc/store/html/index.htmlGoogle paper airplanes or find a book and make that his hobby for awhile.
Poor baby and my condolences for not having much of a selection of schooling options.
Also, I have recently read and would highly recommend the book "your child's strengths". By Jenifer Fox, which is like you were saying how to focus on developing a child's strengths. You're not going to find your life passion inside your personal area of weeknessz.
