erratic sleeping patterns - middle of the night insomnia?

[worriedwithfear]

Over the last few months now I've been experiencing on going night time symptoms where I'll wake up anywhere from 130am - 530am sometimes with this slight feeling that I needed to pee. However I don't always end up actually peeing. The times I have been to pee during these early mornings I can void around 400/500ml so not an excessive amount. Around 6am I can fall asleep again for another couple of hours. Sometimes though I won't go at all until the morning around 8am before work and other nights I have managed a decent sleep of around 6-7 hours. Some nights I'll wake up momentarily only to fall asleep but it's when I wake up around 330-5am and I'm wide awake as if I've slept 8 hours that bothers me. I've heard of something called middle of the night insomnia, is that anxiety related though?

I don't have any other symptoms apart from this slight need to pee (and as I said I don't end up peeing 50% of the time) but no nausea, I don't feel thirsty, never feel tired, or have any pain anywhere etc.

During the day time I've had mostly normal urination patterns/frequency.
These night time issues though are still bothering me a bit.
Also I had my prostate/PSA test and that's all normal, urine culture/test came back normal too. Personal blood sugar monitoring was normal too.

So I'm not sure what this could be. Doctor suspected it could be over active bladder but then I think that would be frequent urination with small amounts but to be honest it's these choppy sleeping patterns that are bothering me now more than anything, less so the urination patterns (which are mostly normal other than the occasional void waking up).

[worriedwithfear]

I thought I'd update this thread.
So since I last posted, from around the end of March my sleep improved. I was sleeping through more nights than not and this waking up in the middle of the night seemed to end. I didn't really change my diet or anything, if anything I have and am still trying to decrease my overall sugar intake. So that's almost two months of much better sleep patterns, at least they were less erratic.

But now for the past 4/5 nights it's back! On Monday I woke up at 2am, the next night again at 230am, last night at 215am and so on after just an hour or two of sleep. And it's that wide awake feeling where I cannot get back to sleep. Eventually I do get back to sleep around 5am and manage to sleep for a few hours so thankfully I'm not too sleep deprived and still feel largely well rested.

Anyway this is frustrating. I do have alot of worries and frustrations at the moment but like I said before I've had these for many years. Also although I do have a fairly large tea/coffee intake every day, I haven't changed this intake so it can't be my diet. No other symptoms really. Urination patterns more or less normal, no tiredness, hunger, thirst etc.

So why am I sleeping well for weeks and then suddenly not sleeping well again with the middle of the night insomnia returning?