I just broke up with my boyfriend and I think it was a mistake?

I was dating one of my closest friends for almost four months until a few days ago when I broke up with him. At the beginning he was great, and he would bend over backwards to make me happy. Lately there's been some drama in our friend group and he started treating me different. Then my mom had a conversation with him just to get to know him and he basically thought she was telling him he was possessive of me and that he'd scare me off, so when I went on vacation after he barely spoke to me, even when I came back and was very sick. So I was very upset and thought that he just didn't want to be with me, and I made the decision to break up with him. So when I did, we both agreed we were better as friends, and so we had a great visit after and are still going to grad together (his idea). But afterward I actually started thinking about how I felt and realized I wish I hadn't made that decision. I don't know if it would work out in the future but I realized that we could have given it another shot and at least ended the school year off together. We're both upgrading next year too so that's either a good thing or a bad thing. He seemed like he was on the same page with the breakup, but we've been talking and we're both going through the "you don't realize what you have til it's gone" thing, and I don't know what to make of that. (This was my first time breaking up with someone so I don't know how well I handled it). Any advice would be much appreciated.