Anyone else discover they have a hematoma?

Erika • Finally preggers! Can`t wait to meet my new valentine. <3
We got to see our little sweet pea today. We got to see it's little heart beat. Everything looks great except I found out I have a hematoma on my uterus. They think it's from implantation and I'm not allowed to have sex until my next sonogram they said it's common but not normal anyone have more info? I was too overwhelmed by seeing the sonogram to think of questions.