Coping with an ex girlfriend..?

My current ex girlfriend and i were together for a while and i thought i loved her and everyday she would tell me that she loved me and how she wanted to be with me for a long time, but i texted her one day and asked were she wanted to go and she says "no its not even like that anymore" and i was like "what do you mean" and she said "your just stupid i don't like you and you don't mean anything to me ..your worthless and i am breaking up with you". I was just in complete turmoil i haven't talked to her since and i don't know how someone could do something like that to someone they supposedly cared about..I am just destroyed emotionally and mentally i don't feel the same, i don't think the same, and no matter what i do i am always thinking of her. I really need some help any ideas that work for forgetting about an ex, please!!! because if i can't figure something out soon i know i am going to do something very stupid because i cant live with a constant heartache much longer.