If it happened at 3AM when you got up to go to the bathroom, it was most likely orthostasis (a drop in blood pressure following an abrupt change of position from lying to standing), which can be as bad as to cause syncope.

There are many antipsychotics out there, besides Seroquel and Invega. If Invega works for you and in particular if it does not cause lactation in you, it might be the right med for you. But if you are willing to try other things and the pdoc is willing to experiment, there are many others now on the market.

The pdoc should have told you not to change position abruptly anymore. When you wake up, sit on the bed for a bit and then only get up to a standing position.