My menstrual cycle has been erratic. My last period is about two weeks late. I have ruled out pregnancy. I am concerned because I am experiencing abdominal bloating and pressure. Could this be a sign of a serious medical problem? Bloating is not a new problem for me, but for the past three days I have felt like I have rock sin my stomach and have battled mild nausea - which is not uncommon for me during menstruation.