I feel sad and lonely

Me and my boyfriend of 4 years broke up about 3 weeks ago, I was fine at first but now I feel very sad and lonely. I don’t want to get back with him, I don’t regret the breakup it’s just before any little free time I had I spent it with him, and now I don’t know what to do with my free time. Most of my friends are busy and I find myself at home alot of the time. I guess this is just a rant since I didn’t have many people to talk to about this, thank you for reading and if you have any advice please do comment