It's horrible that you dad would be ashamed of you. Parents should always support you no matter what grades you get in school. You aren't a failure or a loser at all, it seems to me your environment and the people you associate yourself with are causing you to feel this way. You need more self worth and you need to believe in yourself, that way you'll have better friends and you can be your best self. I haven't been in a committed relationship and I'm several years older than you, yet I'm alright with things. You don't need a girlfriend and if you really want one, work on yourself and don't worry about competition or other people, worry about fixing yourself then you'll have what you want. Adulthood can be lonely and awful, but again work on yourself, be the best you you can be, and try hard, and don't hang around people who don't appreciate you. Find those who represent the best parts of yourself and don't let people and situations dictate how you're meant to feel about yourself. If other boys take the girls you like then so what? Go find the girls you love you and want you. I've been in a goth-like phase before, people get into that because they feel their lives are terrible and life is against them, but the truth is you're against you, and the only way out of that is to find the people who share your qualities and make friends with those who see the best in you.