When the caregiver has no "care given" to them...

I feel so selfish writing this, almost like my priorities aren't straight here, but I've been dealt another blow and I feel like I'm ready to break...
A little history, I've dealt with cancer a lot in my life. It seems like everyone has, and it's more and more frequent, as we get older, more and more people are going to have to deal with this hurdle at some point. At 15, I lost my grandmother to leukemia...I was in complete shock, almost like I fully expected a complete recovery. I didn't understand the gravity of the situation. When I was 21, I was diagnosed with cervical dysplasia, stage 3, I was beyond terrified, convinced I would die, but I had a surgery and it was removed successfully. Check ups have been fine for several years. until recently I had an abnormal pap and because I have had so much going on I haven't had it checked further. (I know, I know..bad..I will and have to go) About two years ago, my best guy friend was diagnosed with bladder cancer. We were really close, but he sort of distanced himself while going through it and about 6 months ago he moved to NYC, has a new girlfriend and barely maintains any contact with me, and it hurts so much, especially with what I'm going through now: Which is my point I'm getting to. (Sorry I'm so long and rambling) I've been dating this guy for about a year and 3 months. He has serious problems, maybe depression, though not clinically diagnosed. Things have never been great from the very beginning, as I found him very wishy washy unsure of what he wanted, closed off, sometimes even hostile but never mean. After 2 months of dating, he broke up with me, this was about a year ago. Last November, he came crawling back because his best friend was diagnosed with a very rare form of leukemia. My bf was a mess..he was very close to his friend. For months I did EVERYTHING, I took care of him, made sure he had food, did all the laundry, held him while he cried..if he wanted to talk he did, but most of the time he did not. He expressed how indispensible I was to him, how much he needed me, in life, that he would never hurt me again. For about 5 to 6 months I took care of him without getting much back, he never wanted to go out, a lot of times he was emotionally dead or it was a roller coaster. At this point we were basically living together, and he would say "I need to be alone today." Then he would go back to needing me. Then I found out that he had been addicted to painkillers and was going to get off them. Again, I was there through it all. It was a lot, he claims he hid his misery to me, but I wasn't perfect all the time, I would get frustrated from always being the support, but we got through it. Through all this, His friend, thank god, started to do better, and my bf needed me less and less. The great amount of verbally telling me how appreciative he was of me decreased and decreased, and he pretty much is an entirely different person. I guess I just needed to be needed. Anyway, here's the main point of all this. 2 days after my birthday at the end of August, my dad was diagnosed with myoblastoma, a very very deadly type of brain tumor. When I told my bf he downplayed it SO much, and it hurt. I was a wreck..it was my father and it was a horrible diagnosis! Sometimes he would be great and try to keep me thinking logically, but most times I just wanted to hold on to him and cry. Once I was laying in bed and he just sat there and I yelled "Why can't you at least hold me! Why is it so hard!" And we got in a huge screaming match (the only time he's ever raised his voice at me) Immediately afterward, he apologized I spent the night locked in his arms. He made no changes to his ways though, he continued going out getting wasted every Saturday night with his friends (which he had been doing since May, when he cut out the painkillers from his life), sometimes coming home, sometimes not but never communicating with me, which I expressed that I knew he needed a realease but I needed him too. The last two weeks he seemed very depressed and kept telling me he was sorry he wasnt better for me, that he could be better for me, that he loved me more than anything. Then, two Mondays ago, he broke up with me. He said he needed space, but I panicked and wanted black or white, it's hard enough being in this gray area everyday with my dad. He says he's never been through something like this before, being the main support system for someone with something so serious, that he loves me and I've done nothing wrong but he hasn't been happy for a while in the situation. That if it needs to be black and white, we are done, broken up. I am in shock. I've heard from him a few times in these two weeks but I'm having the hardest time processing this. All I've done for him, I've supported him with his sick friend, his pill addiction, I GAVE HIM EVERYTHING! How could he do this to me? How can someone leave someone they love when they need them most like this? I am in terrible shape and I feel guilty because I'm not my best when I get to visit my father. I feel so incredibly selfish taking emotional support away from my dad when I'm so worried about my own self and this stupid jerk who left me through this. Problem is I still love him and it's so hard. I just need advice if anyone else has been broken up with while being a caregiver, I feel like I have nothing left to give that I'm going to break. Almost like I have no one to lean on and I feel SO selfish worrying about this crappy person who broke my heart when my father is so ill. Please help. I wish you all the best and thank you for listening to such a long and rambling post.
Best Wishes.