Blood clots post partum

I’m 3 weeks post partum on Tuesday. I had stopped bleeding for maybe a day or two I think about a week after birth. It restarted, and I’ve been bleeding since then. Today a giant blood clot came out of me. Along with alot of blood. I haven’t really had blood clots until this point. I notice maybe small pieces when I pee sometimes, but nothing like this. I have a OB appointment Thursday but they have no after hours number. Should I go to the hospital?