Help understanding problems with breakups

First of all, thank you all for having this beautiful forum to discuss such a thing that is getting more and more irrelevant to todays society.
Let me start by introducing myself, I'm a 20 yo gay male, I live in a regular family, we dont have any money related problems, my family accepts my sexuality with no problems, I have a great relationship with my parents. I study computer science at night and work at day to pay for my college. I dont have much hobbies neither much spare time. I had 3 relationships in my life, all of them LDR, all of them ending um breaking up not badly, the problem is that I simply cant keep just talking with my exes, even after 4 years of the end of the relationship, I still feel melancoly when I talk with any of them. On the last breakup, of a 2yo relationship, I started drinking heavely, had depression and I needed to start taking medicines for it. I simply cant undestand why I cant talk with any of my exes, I just feel a bit of hate and sadness about them, all of them, and I simply cant tell why. I basically cried myself to sleep the last month after the last beakup, now I'm a numb state, I feel absolutely nothing for no one. Maybe you guys felt the same way and could tell me how it went for you.

Thanks for you all. Sorry if my text is not perfect, but english is no my main lenguage and I simply dont know anymore where to run, tried family, friends, food, drugs, alcool, nothing helps me.