Help? If you can..

Soo I downloaded this app in June.. my period was “regular” to the point it would be at most a week late.. but always in between on time to a week late.. then randomly, it decided to skip a month.. my last normal flow was august 20th.. I didn’t have a flow in September, it came October 20th. None for November.. I was kind of expecting it to be December 20th.. but it came on December 25th.. now I am feeling so weak and fatigued.. I’ve been passing small clots and it’s pretty heavy.. but not enough to use a bigger tampon.. (I use regulars but have been filling them a bit faster) I do have PCOS and have been having more pain recently with it.. almost to the point of cannot move..

I am not on birth control.. I have no idea what’s going on..

I do have an OBGYN appointment in January.. does anyone have any insight or opinion on what this could be caused by? 🥺

TIA.