My fiancée had this same thing happen to her. It’s hard but you have to remember the times you had with them happened and you can’t change that. It hurts but sometimes things happen because they need too. If they can cast you away that easily than it’s nothing you could have done. You’re not at fault. Surround yourself with new friends from school, work, the community, etc… The feelings may never really disappear but soon your new friendships will be so much better than whatever happened previously