Heartbreak Causing Depression Relapse?

I have had depression & anxiety since my Sophomore year of highschool (I am a sophomore in college now). I've gone through times where I've managed it better than others and times when it has come back bad. My senior year of highschool and right before I started college was my lowest point of all. Once I started college, I started to think that everything I had done to manage it had made it go away for the most part. So from there I started to try to teach myself to get out of negative thinking patterns. I eventually started therapy at my university during the beginning of my Sophomore year with the goal of becoming a more postitive person and healing from the past. However, this past November, I didn't realize that I started to get bad again. My roommate claims she saw it and says that she noticed me using lots of distractions. She said she started to get worried about me but didn't want to tell me unless I brought it up. I didn't even realize that I stopped seeing all my friends and hardly left my room. I guess I was in denial. I had also been talking to a guy since summer that I really liked. We dated all summer and went away to different colleges but still talked. We couldn't date because long distance is too hard and then he graduated. When holiday break came in December, I ended up seeing him but I didn't talk much because my anxiety was suddenly so bad that day for some reason. After that, things weren't the same and I knew it was over between us. I talked with him and he still wanted to be friends but I said I had to move on and it was too hard for me to even be friends. I think after that, I was in shock because I didn't care that much. From that point, my anxiety and depression got consistently worse. Now I am back to where I was. The worst part is that I think the whole thing ending with that guy is finally hitting me because it's all I can think about now. I thought it was weird how it didn't affect me at first because I cared so much about him but now it is. So now here I am, home for break from college again and I feel like I'm almost back to where I was senior year. I feel so stuck. I don't even know what to do anymore because it just feels like it always comes back. When I was up at school it was even hard to go to classes and do schoolwork and the last thing I need is it affecting my grades. The more I think about it though... what if I'm just heartbroken? What if this isn't me being depressed? Maybe I am overthinking all of this but I feel like I need to figure out what is going on with me so that I can fix it. I've been depressed before so I feel like I should know but I just want to make sure. I mean maybe it pushed me over the edge into my depression again? How can you tell if you're depressed or just very heartbroken? And what are you supposed to do about depression that just keeps coming back when you've tried so many things to manage it. I just don't know what to do anymore. I hate living like this. I feel like I have so much to be happy about and it makes me feel guilty for feeling this way.