Emotional wreck

I posted a topic about me being a bitch towards my bf he breathes or talks it upset me i go off on him for any reason i can this week i havent been in the best mood when im not yelling at him im crying to everyone else everybody commented on my topic asking if i was pregnamt i took a cheap one it came negative but my period is 4 days late is this pre pms symptoms or am i haveing symptoms with no period this week. I swear im not depressed any ideas???