Hi,
Your profile shows that you are male, but I'm answering this as I would in response to a female.
Honestly, the only way to diagnose this concern you have about not getting wet very often, would be to seek advice from your doctor/gynecologist. Women experience dryness from time to time, it's not uncommon; this is one of the reasons why lubricants were created. If you are still worried, you should make an appointment with your doctor soon.
Take care
As I said before, dreams are not needed to get sexual arousal. Give rest to all sexual activity and you will get arousal automatically.
Hi,
There could be a few reason for this, such as: any medications or birth control that you might be using ( which can make you feel 'dry'). Or you might be experiencing a change in estrogen levels ( hormones can have an affect on wetness/dryness). You can always speak with a gynecologist if it continues; meanwhile there are a variety of lubricants on the market that may help you.
Good luck
Dreaming of sex is a waste. Taking porno as help is also a waste. You will get sexual arousal in a natural manner which is always good in the long run.