Fearing that my relationship is becoming unhealthy?

I've been in a relationship since January and for the most part thing were going very well. At the beginning of June my bf started the police academy and it's pretty rigorous. Things were fine until i sent him 3 texts last night asking where he was. He basically snapped back saying i'm driving him crazy. He went on to say that there are 3 things that could break us up: me drinking, me sending nagging texts and me not making an effort to keep my house clean. Long story short-he had a rough day, but i didnt appreciate how he handled things. He has told me before about the texting so that was my bad, but i'm hurt that he brought up us breaking up. He came over last night after this, was grouchy, no intimacy took place, then he went home. he apologized for being grouchy later. I feel rattled by this. Things had seemed great, but with him mentioning breaking up, it doesnt seem that way. I'm hurt. Do i just back off? yes is the obvious answer but i dont want it to be like this :(