What is the difference between mental abuse and then just being mean?

I kinda feel like my boyfriend is being mentally abusive but he’s been going through a lot lately and maybe that’s why he’s being mean.... I don’t wanna leave him because I love him but I’m kinda afraid that I this will turn into more than him yelling at me and telling me to shut up when I try to explain myself and stuff like that. Idk I also kinda feel like I’m overreacting and blowing it out of proportion.