How do you get over the love of your life?

i was dating a girl for 3 years and i was completely head over heels for her she was perfect in everyway i loved her with everything ive ever had i built my entire life around her and just 2 days ago im sitting in bed sick cause ive had swine flu and i havent seen her since i got sick and she comes in and im all excited about seeing her and she just says im not happy ne more and leaves she never gave me a reason for us breaking up and i was heart broken but i tried to cope with it but it was endless pain and it doesnt help the fact that im already diagnosed with depression but i was coping and doing ok but today i get a random call and this guy answers and says hey im your ex;s new bf and just starts rubbin it in my face!! I went frantic and ended up in the floor curled up asking myself why all this was happening to me all at once. Its not the fact shes gone i can attempt to deal with that its just the fact that she says she told one of my friends that she has no care for me at all that im nothing to her anymore. My question for her is and i cant ask her but its if your with someone for 3 years and you say your in love with them and you want to be together forever but then 2 days after you randomly leave you have no care for them ne more and you have a new bf it doesnt make sense to me! I really love her and i truely feel lost without her and i just want ways to help me through this cause i honestly think this could bring me to a new level of depression and it could honestly cause me to give up on everything ive ever wanted. Please could someone give me some good advice i really need it cause my life is a wreck now