Now that I've been on the metformin I have somewhat regular periods with the occasional skip a month.I had unprotected sex with my boyfriend on April 21,and soon after missed my period for that and now I've miss my period for may as well.I've taken two hpt and both have been negative but now I've been feeling more tired and having aching in my breasts and pain in my pelvic area on both sides. Could I be pregnant and a urine test not pick it up?