Hello and welcome to HCM, I understand your concern. You have said that there was a penetration once without condom and after that used a condom. However if semen was not released in the first act, then there are no chances of pregnancy. Also about the irregular periods. It seems that you had periods but they were not regular. even if there was one period after the act with regular bleeding [ not scanty or spotting], then there is no pregnancy from that act. The reason for irregular period may be stress, hormonal dysfunction, excessive exercise or polycystic ovaries. All your pregnancy tests are negative. They come positive 3 weeks after sex if that sex has resulted in pregnancy. So pregnancy is absolutely ruled out. I suggest you meet your gynecologist and get evaluated for other causes and get treated accordingly. Hope this satisfies your query. Thanks for using HCM. Feel free to ask any more questions that you may have. Dr Madhuri Bagde Consultant Obstetrician and Gynecologist