I would go see a neurologist, because what you are describing bears some resemblance to orgasm headaches (which I occasionally have).

I am not clear why you are taking the medications you are taking if your dx is schizoaffective - you are on two mood stabilizers and no anti-psychotic. ???

Also, you take the highest dose of Prozac and two medium doses of MS (mood stabilizers). Would not it be easier to go down on both SSRI and mood stabilizers and suffer fewer side effects from meds? SSRI (Prozac) and MS act in the opposite directions. And Prozac, for me, caused hypersexuality. So regardless of what you do about almost passing out, which is a neurological issue, bring up what you call hypersexuality with the psychiatrist and also mention that you would like to try fewer meds and what psychiatrists would call a more elegant cocktail with less polypharmacy (polypharmacy = many meds at once).