Low self-esteem in mid-20s?

It has always bothered me how low my self-esteem is. But when I turned about 5 I got so ugly. I felt terrible about myself. I didn't really look a little better until I was 19 or 20. Even now I don't feel pretty. I don't take great pictures at all. I have no pictures from elementary school though most of high school and college because I felt like I was surrounded by such pretty girls and I always looked like I was 12, seriously and never looked pretty, I never grew big like other girls or had pretty hair (my hair is very thin, I now can see there's nothing I can do about it). I was also chubby which I took care of and now to this day run 2-3 miles 4 times a week and have stayed fit and healthy so that's one plus. I do have a boyfriend who tells me I'm beautiful every day but I fear he would cheat on me with a prettier girl if he had the chance. What can I do to feel better about myself? I got severely bullied, mainly verbally. I found out I had Aspergers which explains a lot but unfortunately I found out when I was 21 and it seems like it's too late. I've already been through so much heartache. Most people now just ignore me because I'm "slow" or "annoying" but they just don't know me or just don't understand. So before I got made fun of and was told I should kill myself and nobody would care...And now I don't get talked to by anyone but my boyfriend which is almost worse because I feel like I don't even exist and nobody would care if I was gone. I have become more depressed lately. I realize how lucky I am to have such a great immediate family and a great boyfriend but I still feel ugly next to girls and still feel terrible about myself and having Aspergers and being lonely. What can I do?