HELP my period seems to be disappearing

Hi Ladies, so there is no chance right now that I could be pregnant, I’m 33 and I came off of the pill in February this year, at first my periods were running exactly to the apps predictions and was lasting 5-6 days, lately my periods have been coming earlier than expected, anywhere from a few days to a week, even a week and a half once, on top of this they have become very light, with maybe one or two days of bright red blood (sorry TMI) then turning to brown or just spotting. This period started Friday night and was heavy that evening and Saturday but basically turned to just staining yesterday it was barely there at all most of yesterday and this morning, so in effect I really only got one full day of bleeding. I’m really worried that my periods are winding down and thinking the worst, I am going to book in with the doctor but I just wondered if anyone else has experienced this with there monthly cycle?