TMI (picture) Weird/heavy period?

My period stopped and I thought it was finished but I felt like I had started again (a whole day after stopping) and so I went to the bathroom to check and I had bled through my pants. I wiped and there was an abnormally (for me) large clot. I’m bleeding pretty heavily, more heavy than I usually do. Should I be concerned? How heavy is too heavy when it comes to periods? My OB is closed for the day and they’ll charge me for a non emergent call so if I’m still bleeding like this tomorrow I’m going to call and speak to a nurse.

It’s just weird because the blood also seems super bright red to me and I can feel myself bleeding whereas I normally can not.