I need advice

I don’t have people to go to for advice, please help. Sorry in advance for the long post.

My bf and I have been in a LDR for 15 months. I’ve dated before but I’ve never been in a relationship this long because I’ve never felt like this with anyone. I truly love him (which is big for me cause I never loved in my past relationships).

Anyway he suffers from depression and sometimes he gets like angry. He can sometimes say hurtful things and it doesn’t happen often at all so I don’t know if it’s his depression or what. I personally have not been diagnosed with depression but my close family members have so I recognize some signs but my family has never been angry with me like he has. That’s just some background.

Well this is only the second time but he’s been getting angry and short with me. I could tell he felt off so I offered help and suggestions as to what he can do. He kinda blew it off which I get bc he’s not feeling well. Anyway I was goofing around with him and he called me annoying(HE HAS NEVER CALLED ME ANNOYING OR ANYTHING OF THE SORT SO I WAS REALLY CAUGHT OFF GUARD) and said not to say something I was goofing around about because it reminded him of his ex.

So I asked him why bring up his ex, he’s done it before and they broke up 7 months before we started dating, but it’s been like over 2 years now so I don’t see how he’s still hurt about it.

I asked if he was over her and he got mad and decided to go to sleep.

I honestly was hurt and I dreamt he was with his ex again and I told him. He told me not to think too much about it (basically not to talk about it and move on). Am I overreacting? I feel like he’s not completely over her, which in the beginning of relationship I understood but it’s been a long time now.

I’m not used to LDR’s or long relationships in general. It’s all new to me (he’s been in one long relationship before me. About 2 years) and I don’t want to lose him since he’s the first I’ve ever loved like this. There are some other issues about the relationship but this happened most recently.