Help period literally

Millie

So I thought I finished my period but just woke up to a pool of my own blood and this massive ass clot is this a normal size also can someone please tell me why I have been on my period for almost for like 25 days asked my gp

and they said they couldn’t help I’d have to see a gyno but I couldn’t get a appointment till November 9th so please any suggestions on how to stop it would be a lot of help