Struggling with depressed ex boyfriend

Hello, I'm new to this forum. This will be long, I apologize, bear with me.

My now ex boyfriend and I had been dating for almost 2 years, we had a very loving relationship and were initially pretty good about communicating and talking any small problems out. When I met him he had a pretty big weed smoking problem, smoking once or twice a day, every day, feeling like he needed it to calm his nerves. Half a year into dating, he decided to quit and I helped him through it. It was difficult for him but he eventually stopped and felt/seemed a lot better in terms of his anxiety. Last September (2017), he started at a new school and became very busy with his work. We weren't able to see each other very often, we live 8 miles apart, and are both busy with other things. In the month or two before breaking up, I began getting bothered with him because even when we both had free time, he didn't make very much of an effort to spend time with me. Then one time, I offered to come to his place and spend the night, which we didn't get to do very often and he normally would have been ecstatic about, but he asked me if I would mind not because he was really tired and wanted to hangout by himself.
I boiled over and started an argument about how little we saw each other and how it was always him who was canceling or unable to make it. He said he didn't know what to do, that he was sorry and that he had been feeling really depressed lately. We both have serious histories with depression and anxiety, but having seen him so little, I hadn't noticed much of a change in his behavior other than his disconnection from me.
We decided to take a break and talk about it in a week. When the break was over, my ex said that he thought it was the best for both of us if we broke up. He said that in his ideal world, we'd always be together. He told me that he loved and cared about me, but that he was having serious depression and needed to deal with it on his own. He also said he had started smoking weed heavily again and was trying to get sober. He said he knew he was being selfish, but that he had to do it because our relationship wasn't what it should be.
Initially, even though I agreed that this decision was in both of our best interests, I freaked out periodically and tried frantically to contact him. This probably didn't help the situation; he didn't answer many of my texts and when he did, he just wanted the conversation to end. He just kept telling me that he needs time and that he couldn't deal with this right now.
Fortunately, I stopped a few weeks after the break up and didn't contact him for a month. That month was incredibly difficult, it felt like years, but I slowly adjusted to life without him in it. That's not to say I didn't still struggle, but I definitely calmed down and was able to process everything that had happened.
Anyway, after about a month or so, I still obviously cared about him as a person and wanted to see how he was. I felt pretty confident that I could send a non-threatening text just to ask how he was doing, without expecting even a response.
A bit to my surprise, he did respond and said that he was okay-ish and that he hoped I was doing well. I know he feels guilty about everything that happened so I told him that I wasn't mad at him and that I was here as a friend if/when he wanted. He said thank you and apologized again for what he did. I told him that I knew he was sorry and that I just hoped he was still trying to get better because that's the most important thing right now. I got no response after that and it's been a few days since. I feel okay, I'm still moving forward in my life and thinking about it less and less, but there's no doubt that I still care about him deeply and want him to get better, for his sake, not our relationship's sake (although that would be ideal, I'm not counting on it).
For as long as I've known him, he has had therapy appointments with his psychiatrist once a week or every two weeks. He's always taken medication for his anxiety although I'm not sure what it is. When school started for him this year, he told me he was too busy and was seeing his psychiatrist less frequently. I'm sure he's still seeing him, I think his family knows how important it is, but I'm not sure how frequently. Having been seriously depressed in the past myself, I feel deep empathy for what he's going through and understand his logic in making this decision. I am taking good care of myself and all that good stuff, so I don't really need that kind of insight.

I guess I'm just wondering if I did the right thing in contacting him? I know not to count on it but I'm also just wondering if there's any hope for our relationship? Does anyone have experience with depressed partners withdrawing from serious relationships?
Any insight or thoughts into my situation would be greatly appreciated.

Thank you!