HELP ASAP

So I’m really freaking out right now. I had my period last week and i just got off of it on Saturday. I wasn’t bleeding at all Saturday or yesterday so i thought i was finished. On Saturday i was experiencing horrible stomach cramps and nausea. I was also experiencing a constant rush of anxiety. I wasn’t sure why exactly. So today is the following Monday.

*now this part is kind of gross*

Right when i sat down on the toilet today i could just feel myself bleeding profusely. And then a huge clump fell out. When i looked the clump was about the size of a fist and dark in color. The rest of the blood was fresh. So what the hell is going on with me? I’m not pregnant but could it be possible that i had a miscarriage without knowing that i was pregnant?

Note: This is not a normal thing for me. My periods are all very consistent and very light. I usually have cramps in the beginning of my cycle but they usually stop by the third day. My periods are roughly 6-7 days long and i started on November 17. Today is the 26.

Please someone tell me what is going on thx