Missed period but not pregnant..please help:?

My tubes are lasered shut, yet I have not had a period in a month and a half. I feel bloated and I feel tired. I took a pregnancy test and it was negative. Is it possible I have a tubal pregnancy? If so, wouldn't it show up on a pregnancy test? I cannot figure out why my periods are so messed up lately, to finally stop? Im only 33 years old, so it is highly unlikely it is menopause...