Can to much stress cause a woman to miss her period!? having cramping here and there. but no period. been very stressed( new baby too 3 mons old)

Yes, but..: If you are just 3 months post-partum it is also possible your cycle has not returned to normal after the birth and you could skip a month. The other possibility is pregnancy, so if you are having unprotected sex you need to do a pregnancy test to make sure that is not the reason. Otherwise, the stress and life changes (sleep, eating, etc) that accompany a new baby certainly can swing your cycle.