Would you be worried too?

Long post but please read.

So my boyfriend and I have been together for 3 years on July 8th. Our relationship has been pretty great overall, every time we have an issue we communicate and come to a conclusion and fix it. I have always felt like he has been so in love with me since day 1. He wants attention from me / gives me attention, he tells me how pretty I am and how much he loves me, etc. But a few months ago he told me that he has been depressed for a while and he never told anyone earlier because he thought it’d go away. He cried and cried about it and I helped him tell his family, which then resulted in his dad getting him an appointment with his therapist. My boyfriend went to the therapist and he said it helped, but he never went back. Since then he has been mean to me pretty often, which then results in me wondering what I did wrong and he constantly blames me for every argument we have or every time he yells at me. And every time he yells at me he says things like “I’m going home, I don’t even want to be around you” or “you’re so mean to me, I don’t know why I even came to see you.” And I’m sitting there in silence because I don’t know what to say because I didn’t do anything wrong. On top of that, slowly over the past year he has been VERY protective over his phone. In the beginning of our relationship we could trade phones for fun with no problem, but now if I even lay a finger on his phone he gets so pissed and tells me that I don’t need to be on it. I used to have his Instagram logged in on my phone and he didn’t care, but then when he found out I had his Facebook on my phone too (even though he told me I could have it on my phone, I just forgot to tell him that I had it) he flipped shit and changed all of his passwords so I was logged out of everything and I couldn’t get on it anymore even though he’s the one that told me he didn’t care. Because of my anxiety, the only thing that made me feel not so worried about him not letting me touch his phone was the fact that I had his social media and I never found signs of him cheating or anything on there. (There were some things that I didn’t like, but no messages between him and women or anything). I just don’t know if I’m overreacting or not because now he won’t let me touch his phone or have his social media when he used to be completely okay with it. BUT now he has gotten nicer to me after I had ANOTHER talk with him about it, so he’s being so much nicer to me. But I still don’t like the fact that he all of a sudden doesn’t want me near his phone. Should I be worried? What should I do?

Sidenote: he also says things like “when you go off to college don’t cheat on me with a college boy” or he won’t let me even talk to any of our friends that are guys even if my boyfriend is right there. So clearly that means he doesn’t trust me for some reason. And usually when people are worried that you will cheat on them, it means that they are guilty for something they’ve done. I’ve talked to my mom about it and she thinks it’s a little sketchy too.