Anyone else experience this?

Okay so I’m 13 weeks pregnant and recently had my first ultrasound a few weeks ago which was absolutely amazing! But while they were doing the ultrasound they found a lot of blood in my uterus.. she said they weren’t extremely concerned but they are keeping an eye on it and it was definitely something to kinda worry about. So has anyone else on here had this happen? And what happened? I’ve extremely worried about it and can’t stop thinking about it. 😢 and I would like to know what other went through with this.