Follicle checks??

I started clomid this month. I’m currently in my two week wait and had an ultrasound down 2 DPO. I saw my primary today and he said I have a 17mm functional cysts in my ovarys, and he said that like it’s a good thing..? Is a functional cyst the same as a follicle?! I see my OB soon but I’m just so confused... he also said my endometrium is thickened to 15mm and that might make it difficult to conceive.... I thought it’s suppose to thicken? Lol heeeelp