Where can I start...

I am very irregular I haven't had my period since August uuuuugh I know!! Can someone anybody please tell me why yesterday I thought I had finally got it. I went to the restroom whipped and there was blood. In the paper and in the toilet! Went out bought pads. And during the day I was expecting to keep on bleeding thinking it was my period! But no, no more bleeding!!! What happend? Why does this happen? Anybody please... Before hand thank you for reading and responding if you do so. ♡