I’m 42 Years Old And 8 Years Ago I Had

I’m 42 years old and 8 years ago I had my tubes tied and I had where they burn the lining of my uterus and there was a chance I would not get my period again but of course I did and have been very regular since then, but now I am missing periods always having to do pregnancy test that are always negative (thank God). So I’ve been going like every other month with my periods but I’m now 40 days late and want to know what is wrong with me?