No period.. two negative pregnancy tests.. not on birth control

Ok so I haven't been on birth control since October. My (ex) boyfriend and I were using condoms.. he broke up with me on March 7th.. I haven't had a regular period since.. I had a two day period(?) about a week after he broke up with me, lighter then normal none of the other normal side effects like tender breasts and cramps.. I've actually taken 4 pregnancy tests all negative.. if I count the 2 day period, only a couple days late, if I don't I'm really late.. anyone have this happen?