Iwtl how to get over a past relationship when I still have to see them every day

I (22f) broke up with my girlfriend because I found out she had been lying to me about a lot of things. We have been together for five years and lived together for three of them. We have all of our classes together this semester and next. I want to learn how to get over it while still needing to see her every day. I want to learn how to stay strong and not go back again because it’s hard. I want to learn how to like being alone again without the option of a significant other to go to when things get hard.