Tips how to loose feelings?

so like my ex- gf and I broke 6 months ago up. But we kept in touch ... bcs of that it was rlly hard to loose my feelings. 3 Weeks ago she finally blocked me. We had another fight. after the "first" heartbreak from her I promised myself I never gonna cry about someone like her. the day before she blocked me I saw her on a festival. I was sooo down. I only wanted to cry. Which kind of surprised me. 

yesterday she wrote me a anonym Messages on a App. I know it was her(hard to explain but yea)

i was kind of cold. I didn't feel anything. Like she never rlly mattert to me. But I look after her everywhere in social media. its so strange. Like someday I'm over and the other I miss her so much that I wanna die.

rn I'm kind of neutral but I miss her smile lol.

any tips how to get over someone????? hahaha