Small brown blood clot, brown spotting amd nausea. 12 weeks pregnant.

2 week ago, I went to the ER for bright red blood that flowed like a moderate period. It lasted for 2 days. The ultrasound show a healthy baby with a heartbeat of 176.

Friday, I went for an ultrasound for regular screening, a healthy heartbeat of 167. No concerns.

Bow, I noticed the brown clot the size of a BB pellet. Should I be worried?