Why do the suicidal thoughts keep returning?

It just seems like it's on and off again. I feel like it wouldn't matter if I just ended it but I'm afraid god would not except me into heaven. But I'm already in hell so I guess it wouldn't matter. I have very low self-confidence and insecure. I'm almost 17 5,9 232lbs so I'm pretty big and I've been going to the gym for a couple months but I don't feel any smaller or stronger. I stopped drinking pop and rarely eat fast food anymore. I just hate who I am and wish something would kill me. I feel like dissapointment to my family. I tried smoking weed because it's supposed to make u happy but it did nothing. I've never had a girlfriend because of my insecurities and lack of confidence. I'm very shy and can't make friends easily. I don't have anyone to talk to, I would feel to embarrassed telling my parents. I don't know where to turn, I just don't want to be alive. Is there any hope in being happy and proud of myself? Thanks for your time.