You need to watch your language on here for starters... There is nothing you can do. You pick up and move on. I take it this must be the very first time you have had to deal with this?? Dating people gives one an opportunity to weed out the undesirables. You are, unfortunately, the undesirable one this time. Go out and find someone else. Learn from your mistakes and move on. Life is not over.
If they don't care about you, why would you waste your time caring about them? I know it's hard, and I know it sucks, but move on. Use your energy for something positive, because sitting at home wondering what you did wrong, isn't going to help you. Get out there, put yourself into something you love.
You just need to believe that there is someone out there that truly wants to be with you. I know it hard to accept this right now. Loving someone that doesn't love you back can hurt. Decide to move on and do it.