is it possible for me to be pregnant?

I haven't taken my birth control pill for about a month my boyfriend and I had sex around what I saw was my fertile time and he did finish inside me. I've had every symptom I have saw from nauseous, tired, cravings, etc. I did have sore boobs/nipples but it stopped. I was going to take a test until I started my period Friday the 28th. It wasn't a light flow but it wasn't a heavy one. I just got off of it yesterday but I still have the symptoms and I went to the bathroom today and 20 minutes later I had to go again. Is there still a possibility or is it just the after affect of my period ?