Hey there, just a quick background on me, I've had hppd for about 12 years now.
I completely get where your coming from and the best advice I can give is to remember that you are very new to this and in time you will get more comfortable with what is happening.
At first, with me, I would get this sense of rocking, like being on a boat, when I was trying to sleep. This was a very strange sensation and woukd freak the fuck out of me at first. I would and still do get a lot of what I would describe as visual distortions when I'm trying to sleep in a dark room, I'm sure you can relate,