Tied tubes but worried

Minnie

Hi ya'll I had my tubes tied in August after my 4th child via c section but am a little worried. I had my period last month like normal but about a week or two after I had brown discharged. All my life of having periods this has never happened unless I was pregnant 🙄. Now I had calmed my self down and said this is impossible and maybe I'm out of wack because of my tied tubes, but now I'm worrying again because I'm 3 days late. I don't want to take a test cause I'm scared I might see a positive. I don't know what to think of this I've heard people still getting pregnant after but didn't think it was this common. I have no idea what to think or do. Has this happened to anyone???