Pregnant? Help

I had my period on August 2-9, then I had sex with my SO on August 23rd, no protection and finish inside. I was supposed to have my period again the first week of October, because I am irregular but nothing happen. I took 2 pregnancy tests, one in Sept and other in Oct, both negative. About three weeks from now I've been feeling dizzie, light mood swings, discomfort like a pressure on the pelvic area, and sometimes a puncture. Those are the only symptoms. I'm scheduling a visit to Dr next week. Want to know what do you think.