How can i get over the pain cheer me up?

Has anyone ever loved someone so much they can let them go. :( it sucks i must be one of the most sad est people in the world i can not get over her i loved her for a year now and everyday i think about her i cant. get her off my mind. help me please i may need counsel ling that how sad i am she said she felt the same but one day there was a new man :( what can i do really.