Hi.. You know everybody has probably been slammed down in life by the age of 16. Any time you get slammed down on the bottom you just have to get back up. It takes a lot of work, but it's something that you'll have to do. Personally I used to have a lot of people giving shit to me, treating me like shit. One morning I woke up and was determined that I'm not going to let anybody run on over me EVER. Since that day I've worked hardest ever for my goals, and for the things I love all I can say is that nobody has messed with me since.
You have to get your self confidence back, it's the most important factor when it comes to doing good in life. You may feel sad about the things that happened to you, but it's time to move on! It's never too late to move on, the sooner you do it the better! I'm sure that you can get over those things, and move them to the past (we can't change the past but we can make our future) alright?
I hope that helped some.