I Have Had A Very Irregular Menstrual Cycle Since The

I have had a very irregular menstrual cycle since the past year, which has been at least 35-40 days long. I skipped a few months in June last year but it was ok from August. I last had sex on December 2, two days after my cycle ended, which had stated on November 27. I haven't had a period since then and I am really worried. I took 2 tests, one on the day i skipped it and the second ten days after. Both came negative and I have no symptoms. I have always been a little heavy, so gaining weight is out of the question. I dont get headaches or feel nauseous, nothing is swollen and I have no cravings! I did have white discharge for a few days last week but that was it. Is it possible that I could be pregnant?