late period

I have been on the pill for about 3 months. The first month I got my period early so I skipped the placebo pills and went on to the next pack. The second month I got my period during the 4th week. Then, the third month I got my period on time as well but it was very light, not heavy enough for a pad or tampon but also not light enough for a panty liner. I was worried but figured my period was just light because of the hormones in the pills. However today is Monday and I took my last active pill on thursday meaning I should've gotten my period on Friday. Should I be worried that I'm pregnant? Please help.