why is he being like this

together for 6 months , he's perfect we argue sometimes but rarely and never about anything super crazy. but omg this last week he's been blaming everything wrong on me. he's making me feel like shit. making me feel like he's not giving a fuck. he constantly watches my snap score to see if I'm texting other people and constantly looking at my locations and he gets furious when I don't text him when I'm leaving somewhere or got somewhere. he keeps talking about how he's "better off dead" and I guess it's because he's stressed out but he's taking it all out on me. making me feel stupid for talking about prom. I'm sitting in class and I'm just broken . I can't get him to stop arguing with me (little over small shit but it's been all day now) can I please get advice. I don't want to leave him I just want him back to "normal"