I know you posted a long time ago, but if you are still having problems with the frequent urination when trying to sleep, supplementing with the omega fatty acids before bed time has helped me. I take a super complex (omega 3, 6 and 9). I had started doing oil pulling and noticed some improvement in less restroom runs (3 instead of 6 a night), so I figured maybe my body is absorbing the EFAs from the oil. With this reasoning, I decided to supplement with the omegas at bed time. I've improved to just zero or one restroom run a night. However, if I drink anything after 7 p.m. I might have to go one or more times.
This isn't a cure to my sleep problems but has helped with the restroom run problem at night. Oil pulling might also help you with the itching. See the oil pulling forum if you're not familiar with the process.