I feel the same way.
Your burdens are heavy, and your ideas about and experiences with them make them even heavier. I hope you get some encouragement here. You have already made progress by daring to do various things (college, gf, teaching, job). You can get another job, I expect.

I don't think getting involved with someone you were tutoring is so bad - you are both adults and you are not a professional teacher. I was shocked when one of my co-workers got involved with a former student (again, all adults), but apparently it's fairly common in adult education from what I can see.

I bet you could teach ESL. It's what I used to teach, by the way. Considering overseas work, having a disability is an even bigger problem than here in North America. If you teach in Asia, labour standards are much poorer and there seems to be more bias on one's appearance and physical fitness. A physical disability would pose a considerable barrier. Perhaps you could teach in a North American market, though?