Blood clot but no bleeding???

Edit: I’m only 6+3 right now.

Hi ladies.

Yesterday I had some old/brown blood spotting and it stopped pretty quickly. Today around noon my boyfriend and I had sex and I got a little more old blood.

Just now (about 12 hours after sex) I passed a nickel sized blood clot but am not actually bleeding.

I’m totally terrified.

Can anyone speak to this? Or share an experience, etc??