I also feel pathetic. I am 23, have never had a boyfriend of any kind and am still a virgin (which makes me feel really bad), only have one friend at the moment who I rarely do anything with or talk to. I have only had one job in my whole life, but it was only on weekends, and that was 4 yrs ago. I still live with my parents and although I have a degree, I am afraid to even look for a menial job like at a fast food place because I can't function in the real world. It's been a whole year since graduation, but I just sit on my ass doing nothing all by myself every day. It gets so lonely.
I can really relate to the weight issues. In only two years, I have gained about 100 pounds and now I have stretch marks everywhere and don't fit into any of my clothes. I have no life whatsoever, so you are definitely not alone in feeling pathetic!!
I personally don't think that your being a virgin is something to be ashamed of. I'm 23 and I wish I was still a virgin. My ex and I nearly got married, but she wasn't ok with the idea of marrying me because she is and I'm not. The person I fell in love with because she'd saved herself her whole life for me ended up hating part of me because I didn't wait for her too.
Sex is not all it's cracked up to be, but I don't think most people would agree with me. I do hear a lot of people, as they get older, talking about how they regret a lot of the things they've done. There are many people who wish they'd never been physical like that with someone other than their current spouse. To quote my ex, "How much can it really mean to you when you've done it all before? For me it's special, but for you... in a small way it's routine and I'll never be able to change the fact that part of you will always be with her even when we are that close together."
I think there are a lot of people who just try to capitalize on the idea that brainwashing people to believe that there is only one way to be beautiful, and that people have to be superficial to be appreciated, and they have to spend lots of money to "make themselves beautiful"... the people who form those kinds of lies are disgusting. So long as your not liking your body is due to you own feelings and not affected by others perceptions of you... that's okay.
Honestly... childrens' TV shows have a better grasp on reality and a clearer idea of how to be happy than the "adult" world. It is TRUE that: there will never be another one of you. What you have won't ever bring lasting happiness. True happiness is found in what you can give to others. There is something inside of you that you can give the world that NO ONE ELSE CAN EVER DO. You shouldn't allow it to hurt you what other people think or might think. The only thing that can hold you back is losing sight of the valuable things about yourself.
These are also things I struggle with, but I hope I can help you a bit by sharing them with you. Smile, there are a lot of people cheering for you, you just don't know it yet.