Swollen Ovary!?

👶🏻Sweetness⚓️ • Instagram; Hannah.the.gem (add me there for messaging)
Long story short; I'm 12 weeks pregnant and at my 9 week check my doc noticed that one of my ovaries was swollen and advised me not to have intercourse or it could flip over and cut off my circulation (and babies)
Of course I'm going to do what he says but I googled this and found nothing about it. 
Does anyone else know what's going on? How worried should I be? Is there anything else I shouldn't be doing?