Regret having sex with my boyfriend.

And ..no it's definitely not the first time. We are almost 3 years together. We had been having sex from since year 1. We are not living together. But I feel like these months he's just not there for me.. He doesn't make time for us. All he says is that his work is the reason why we can't see each other. We live like half an hour away from each other. Then we would try and talk it out but it mostly ends in a fight "over the phone" and I stop talking to him for days. Maybe 3 days max. Now when we see each other after such a long time I forget everything!! My *** mind just does not think anymore.. Then he would kiss me or give me these looks.. Then I get turned on but after 3-4 min I think back about the reality.. Then I'm like no he won't be that way now..He's different now. He eventually started to understand.. And I will go with the flow and end up having sex with him. When I come home then my mind starts to think again.. Like wtf did I just do?

This has happened a few times now.. About 3-4. I mean the feeling that I get after sex. I feel ..used. Maybe it's my fault that I don't understand him.. But we only have sex about 1 time in a month. So then I start thinking that no..he is not with me for sex.

But then I still end up feeling fucking guilty after it. I don't know how?? What does this mean?? I am so confused..

We had sex today and now I feel depressed.. Because he is gone and Idk when I will see him back.. Most times I see him on Sundays. But today I saw him after 2 weeks and Idk why things are slipping out of control leaving me confused and helpless like now.. 😔

Why do I feel this way..? What should I do?