DM, that sounds a bit familiar to me and the seizures I've had. Epilepsy isn't called the falling sickness for nothing.
All sorts of strange happenings could be seizures, though. I'm sure tumors and heart conditions could lead to similarly strange experiences. Don't let my comments scare you; I am not a physician or nurse. Just make an appointment with your doctor pronto.
There is one more piece of advice I can give you. Get off your feet! If this happens again, sit down, lie down, stay where you are until it passes and you can get help. I think you came to the same conclusion when you were in the bathroom.
Finally, a cautionary tale. My seizures last a good deal longer than your experience, but they are partial seizures that don't involve a loss of consciousness unless I get out of bed and walk around. It took a few seizures for me to learn to simply stay in bed; mine happen almost exclusively in the middle of the night.
I didn't see a physician about my condition until after I had had this happen to me several times - seizure while in bed, get up to go to the bathroom, lose consciousness (i.e. progression from a partial to a general seizure), fall and injure myself - get up. The first couple of times I called 911 and went to an emergency room, but they didn't catch it. After that, I simply dealt with it on my own. Big mistake.
See a doctor. If they don't take it seriously or rush to judgement then get a second opinion. If this is epilepsy, it won't go away if ignored; it will get worse and more frequent.
If you would, please post back here what happens. They will probably want to do an EEG initially.
I hope you find an answer soon.