Break up is messing everything up

So my ex and I were only together for four months. We were friends for years before this and she asked me out in September broke up with me in January. Since we were already friends and knew each other so well we were planning to move in together which I know is super naive but now we’re broken up I don’t know what I’m going to do about a living situation after graduation. We have all the same friends and the reason she broke up with me is because she figured out that she was never really into me romantically which SUCKS like why date me if you don’t know if you like me. She broke up with me over snap not even in person after springing “we should take a break” on me out of nowhere after a great day. Since we broke up it feels like most of our friends have been choosing her over me because she’s invited to things more. Every time I check my Snapchat all my friends and my ex are hanging out without me and it sucks! Also since we’ve broken up I feel so mean because I’m noticing all these things that I don’t like about her and I find her more annoying every day and I hate it. I wish I had never dated her ugh