Bleeding with clots, no pain, baby is fine?

Zee • Mama to a beautiful baby girl named Lana 👼🏻🎀
I'm 15 weeks pregnant. On Thursday, I had a spot of red blood that freaked me out, went straight to do u/s and baby was okay. Then same day at midnight, I had more blood and went to ER, and the next day I had blood with clots that soaked my whole pad, underwear and pants.. I cried hysterically. Went to ER again and baby was okay, they did detailed ultrasound and they couldn't find any blood traces or anything wrong with uterus, cervix is closed and placenta is positioned right!! (God is great 🙏🏼) I was hospitalized and been under observation for a day. Blood lessened but still there especially every time I pee.. anyone experienced anything similar?!! I'm still wondering where all that BLEEDING came from..