I have 2 cysts on my left ovary measuring over 8cm total. can this cause severe nausea? i am not pregnant. if so, what can i do to treat it?

Usually not: Cysts themselves won't cause nausea unless your are having pain. In that case you should seek medical attention asap.

Pain?: Pain can cause nausea - are you having pain from the ovarian cysts? Generally speaking, I would not expect the cysts to cause nausea in the absence of pain. There may be another cause for the nausea in that case such as dyspepsia, GERD, viral illness, etc... See your OB/GYN about the cysts and get his/her opinion first.