SOMEONE HELP ME. Explain what this is?? & if they experienced it

Can someone please tell me (or try to explain) what my results from my ultrasound today mean?? What does a small amount of free fluid in a sac mean?? Also I’m 3-4 days away from my expected period but there’s a chance I could be pregnant. I know my uterus lining is thick due to endometrial hyperplasia. But what is the small amount of free fluid?

My ultrasound pictures today