frightening wake up today

I woke up today and went to the bathroom.  My stomach was in knots as I emptied my bowels.  I started feeling weak, nauseous, and incredibly thirsty.  My heart began pounding and pounding.  I knew I was dehydrating--this has happened twice before in my life, the last time over twenty years ago.  I leaned over into the bathtub because I thought I was going to vomit.  The next thing I knew I was face flat in the tub, moaning from the pit of my stomach and my body covered in a profuse sweat.  I think I passed out for a few seconds.  The strange thing was I remember leaning over the tub then thinking about something completely trivial (work-related?) for a few seconds before I came to and realized I was face flat in the tub.   I was parched--I turned on the bathtub faucet and gulped down a few drinks of water.  Without getting too graphic, there was a mess on the bathroom floor from the other end.  I looked in the bathroom mirror and saw a pale, anguished face staring back at me.  It took me a few minutes to get my bearings, clean myself up, and venture out into the kitchen to get some water and anything to raise my sugar level.  I had no orange juice or gatorade, so I had to settle for almonds, yogurt, and the homemade cookies my mom had sent me.  I had to completely clean the bathroom floor and take off the sweats I had slept in.  It took me a couple of hours to start to feel back to normal again.  I sat listlessly in front of the TV for most of it.  It was a frightening way to wake up, needless to say. I'm not sure what caused it.  The sushi I ate a couple of nights before?  Did I put too much stress on my heart running on the treadmill the day earlier?  Too much wine?  All the above?   I'm a bit worried because I'm currently on Dostinex for a pituitary tumor, and it has been known to cause valvular heart disease in Parkinson's patients taking much higher dosages than I have been.  It's supposed to be safe for my condition, but I wonder if it's having some kind of effect.  It's frightening to have something like this happen when you live alone and may not be able to get to a phone to call for help if necessary.  I'm scheduled to see an Endocrinologist on Wednesday, so I'll bring it up to him and see what he has to say.  I don't think it has anything to do with the tumor, but perhaps the meds are making me more susceptible to certain types of afflictions.  Tune in for an update later.