I'm under extreme stress I'll cut to the point.

I got my period January 12th and had sex with a condom around the 29th (Meaning I was definitely ovulating) the condom broke, as soon as we noticed we stopped, he didn't ejaculated inside of me but I mean precum has me beyond worried 

If I'm following a 28 day cycle I'm a day late on my period, I've been having pretty bad headaches and stomach aches and my acne has gotten a bit worse this past week which makes me want to believe it's pms. However I usually don't experience stomach or head aches, just the acne. I'm also very used to having an irregular period, I've gone months without it, a month with it, back to months without it, etc. But the past 3-4 it has been regular. If I don't get it by the weekend I'm purchasing a pregnancy test. I'd just like to know how likely it is I'm pregnant because I honestly couldn't be more scared, I didn't sleep last night and I've been crying so much.