Please help

So please don’t judge or make me feel bad, I know we shouldn’t have had un protected sex but it happened. I am on the pill and I know that’s only 98% effective but Anyway it happened on February the 8th right after my period. It’s been 2 weeks and 3 days and I woke up with constipation and diarrhea and it won’t go away. I feel super sick and I’m supposed to start my period on the 28th. I’ve also been very moody and emotional lately. Am I pregnant or could I just be sick?? Please help I’m only 18 and I don’t want to take a test yet until I’m supposed to get my period.