I feel so terrible right now

I think somethings wrong with me. For one, I have a delayed emotional response. I'm crying now, I feel like I'm pushing my boyfriend away. I keep dong stupid things sometimes. And I try to be better, I just feel like there is something wrong with me. Like I'm realizing that I can be unwittingly selfish- yet I'm so selfless most of the time(I love to help others, I patiently help out around he apartment and pick up after my boyfriend while he's been working and going to school full time,, for example), I don't know where this comes from. It's like I literally just don't think of the consequences of my actions sometimes, really bizarre stuff.
I smoothed things over and apologized and he went to bed but here I a, crying, feeling like a piece of ****. One of the things he brought up was the time I as driving home, picking him p from work late a while back and I accidentally went thru a stop sign. Yes, it was wrong, but I didn't have the emotional response warranted for the discussion. I did get little sleep last night, but so did he. I was super hungry and had a bite to eat upon finishing the discussion.
Though I do feel like something is lacking in me.
I'm either emotionless, of overly emotional.
While Aunt Flo did just arrive, I don't really think that's the issue. I have mentioned to my bf and my close friend how in the past month I literally haven't felt any sort of anxiety or even feelings of fear towards any situation, whether real or fantasy (movies and the like). It's weird. I've always been an anxious person.
The last time I felt like this I was in college and I had a slight drug problem(which one would attribute such feelings, or lack there of to), but it's been years since I've touched the stuff. Ugh, I just feel terrible.

Ok, So I think I was overreacting, I just felt this overwhelming despair- I was crying this morning uncontrollably and talked throught hings with my bf- he wasn't even upset with me anymore- when we had finished talking last night he assured me he still loved me and he ended up actually going to bed because he wanted to catch up on his sleep and he laid down and then I said goodnight and said I loved him and he didn't respond- which is I guess what caused my downward spiral- he claimed he didn't hear that nd we talked more and he said that it would take a lot more than that for him to leave me- he admitted because he has been more stressed and getting less sleep that things that normally wouldn't upset him as much have been.
So I guess part of the thing is once I start crying, it's hard to stop- I bottle a lot of things up and just all this emotion was wracking my body and he soothed me and now I feel silly. Maybe all this is partially because its that time of the month.

Your emotions are real, though. It doesn't feel good to fight with a loved one nor do suppressed emotions. I'm glad you could talk it out with him. Best wishes!