Could I be pregnant?

So my man and I had unprotected sex on the 7th of February and it’s now the 27th of February. I am on the pill however, I take it within a 3-hour period every. So I don’t take it right at the same time everyday but I take it within a 3-hour period. So he came near my vagina and some was on my leg. Recently I was supposed to get my period and I thought I got it but it’s lighter than usual, mind you I’ve been on this birth control for a year. I also am having a bit discomfort on the right side of my stomach. It may be just a cramp but I don’t cramp much because I’m on the pill. I called an on call doctor and she said the longer I take birth control the shorter and lighter my periods would get. I get headaches all the time, I did have constipation but that went away, I also had a tad bit of nausea but I think It was something I ate. I also have very bad heartburn and have since New Years. I also get really tired but I am a full time student who takes the bus far and I work part time. I don’t have enough money at the moment to buy a pregnancy test or I definitely would. But by the information I gave could I be pregnant?