This may sound strange to many, but this is a serious problem I have been facing since last 9-10 years. My age is 31 & I am a male. I wake up to piss late night every day. At that time I am in a sleeping mind which is quite natural. I remain in full control of myself when go the toilet, but the problem is during urinating in the toilet i feel dizziness sometimes. This starts during the urinating period & becomes very high within 15-30 seconds. I have also fallen on the bathroom floor twice in the past for this reason, injuring my forehead & hand though the injury was not major. I completely feel weak during that dizziness period. So i try to hold something like the wall as a support, until i finish urinating. But strangely i never have this problem when I urinate during the day time when I am not in a sleepy mind. So far I have been taking this issue lightly, that's why I have never consulted with any doctor.
If anyone has any idea about this problem, please share his experience & give some suggestions to overcome this problem.
Believe it or not, but it sounds like you are experiencing micturition syncope
You sink when you pee.
I have experienced it myself but not chronically as seems to be the case with you.
Perhaps you should see a doctor to rule out other causes, but if it's what I think it is, there is no cure - you should probably sit on the bowl when you urinate at night so that you will not hurt yourself if you fall.
Suggest you google the term or check it out on a medical website like www.webmd.com,
but I'm pretty sure this is what you are experiencing.