8w4d. Cyst?

S💕
Had my first ultrasound on Tuesday. Measuring at 9w1d. Not changing my due date because it's less than a week difference. 
But the dr saw a "cyst" with a "blood clot". Said it likely developed at conception. Has this happened to anyone else?  He didn't elaborate too much on it just said to take it easy and we'd check on it in a couple weeks.