We went throught the same thing with our son who is now 6. When he gave up his naps (at about 3 1/2), the deep sleep nights resulted in nightly bed wetting.
When he turned 5, our pediatrician recommended an alarm. His opinion - that the drugs are a short term, not long term, solution, and the limiting liquids just won't do it either. At age 5, they are supposed to be old enough for the alarm to be effective.
http://sleepdryalarm.com/
This worked wonders!!! I would do an Informercial for this product (I think I actually am right now). I agree, that to my son the alarm was loud and scary, but we fought through it and it worked. After a few nights of loud noise, we would place the alarm under his pillow, so it wouldn't be so terrifying to him.
It took a little over a week. Each night we saw small progress... the alarm waking him during urination, then the alarm waking him and us racing to the bathroom, then the alarm waking him and him learning to STOP mid-pee, then just waking when he had to go.
After our success, he fell into a regression a month or so later. So we had to break it out again for a few nights, but then he got right back on track again. We have been free of bed wetting for quite some time now!
It worked for my nephew too.
GOOD LUCK. I know the exhaustion and frustration you are going through...
Sharon