Don't let these so called "Friends" make you bitter. I know that it hurts, but some things in life are the way they are. Do your best to put it behind you. Everyone has had "Friends" like this.
Summon your courage and never give up. Never try too hard to make friends. Always be yourself. If others don't like you for you, then **** 'em.
Do things in life that you enjoy. Things that will make you proud of yourself. When you begin to respect and feel proud about yourself, it will draw others to you.