Am I pregnant?

So im 19, and 6 weeks ago I had unprotected sex (I was on the pill but mucked up the packet before (finished it to early) and I had sex on the 7th day of the packet). I then, around 2 weeks later got my period but it was pretty light (still got red blood tho). So a few days after I took two tests, both negative, and a week later, still negative, took them all in the morning. I have almost finished my next pack of pills but my stomach is getting bigger and im scared I might be pregnant. How likely is it that I am? This is all pretty new and scary for me so advice would be wonderful!