Might be pregnant? Advice?

The last time I had my period was December 13th-15th. I was supposed to get my period January 9th-11th but it just went right over. My boyfriend and I had sex the 6th and I had spotting for a few hours on the 13th. We also had sex on the 15th. I took a few tests closer to my expected period date and then decided to just sit back and wait because I am now almost to my next period date. Do you have any advice? Should I just keep waiting it out or should I go to my doctor. I have been nauseous on and off, nipples are sensitive, tired, gassy. Nothing like my PMSing symptoms (cramping, sore boobs, back pain)