Is he emotionally blackmailing me?

I’ll try and keep this as short as I can. I was with my ex for a little over three years. He suffers from depression but was only diagnosed a year ago so for a lot of our relationship he was moody with me and took his issues out on me. We were happy sometimes but he would always do something wrong. I would break up with him and then he would beg me to get back and that he had changed and I would give him another chance. This has happened twice now. However, 3 months ago he broke up with me because he didn’t think we were right for each other. I warned him that if we broke up this time I wouldn’t be coming back. He didn’t contact me at all for two months. I was devastated but I also knew it was probably for the best given the way we had been with each other and all the fights we had.

A month ago he started contacting me again saying he wanted to be friends. I was happy with this as I had moved on in the two months and I was starting to see that this breakup was actually better for the both of us so I said yes let’s be friends. Now he is constantly texting me and ringing me asking me to get back with him. When I say no he keeps saying he’s a changed man and I owe it to him to give him another change. I’ve been very firm and said I don’t want to go back but it’s like he won’t take no for an answer. I feel like he’s going to keep harassing me until I get back with him and it just feels like blackmail. Everybody keeps saying to cut contact with him and that’s all well and good but he keeps saying things like “oh I don’t know what I’ll do if I’m on my own” and “can you take my antidepressants off me because I’m afraid I’ll overdose on them”. His family aren’t very supportive so I feel that it all lies with me in making sure he’s ok. Right now I feel so trapped and like I’ll never be free from his grip! What do I do?