B"h, I'm nearly half a year clean. However, I seem to have a problem with nocturnal emissions/re'iyat keri: I know very well that at the start of PA sobriety, men tend to have many emissions as their body adjusts to the cleansing process. Afterwards, it comes down to controlling your thoughts during the day.
My problem is that I'm pretty well along into my sobriety and I work hard to control my thoughts. However - I still get many nocturnal emissions - often times even during a daytime nap. There are many days that it seems that I wasn't at all thinking about anything bad, or "at least" had a single thought for a few moments - and yet, I still see keri! 
I was wondering if anyone has an idea what's going on? Could there be another cause to this? Maybe stress?

How old are you?
I used to get a lot more in my early 20's than now in my mid 40's.

One thing is, try to think about something non-sexual before you sleep.
I find that what I think about just before I sleep imprints itself on my thoughts during sleep.

Sorry for only replying now (I've been busy lately). Yeah, I'm in my early twenties. I'm well aware that wet dreams are more common at a younger age, and yet - I feel (though I may be wrong) that something מוגזם is going on. Perhaps my brain is so messed up that even one slight thought that slinks into my head causes an emission?

I've gotten to a point where before I go to sleep - whether at night or a daytime/noon nap, I fear I'll wake up after having an emission.

I do work hard to control my thoughts, and yet - it doesn't seem to help. I used to track the number of emissions I had, until it got to too many and I stopped. Perhaps there is no "normal" average?

Therefore I was wondering whether it's possible that it's actually stress related, or perhaps caused by something else instead?

This must be upsetting and confusing.
Perhaps see a doctor, because if you are having so many, then there may be a medical factor?