is it normal to get in a bad mood with your boyfriend?

so my boyfriend and I have officially been dating almost a month now, and for some reason, the past few days I've kinda been upset with him but I have NO idea why and it's upsetting me. it all started 4 or so days ago with a very stupid little fight that's over and done with, but I've still been a little bit annoyed ever since. I saw him yesterday and everything was totally normal, but today he was sorta weird and didn't talk to me half as much as he normally does (he only called me once for like 10 min, when he normally calls me 3-4x a day for at least an hour cumulatively). he asked me earlier why I was sad and I told him I was fine bc I didn't know what to say/didn't want to even try explaining and when I asked him the same he said nothing was wrong. I felt myself being short w him so I just said I was going to bed and now I'm sitting here feeling like crap when I a) don't know why and b) don't want to feel like this. is this abnormal? :/ I feel guilty