The thalamus acts as a relay for information from the senses to the cerebral cortex (the covering of the brain that interprets and processes information from short- to long-term memory).  During most stages of sleep, the thalamus becomes quiet, letting you tune out the external world.  But during REM sleep, the thalamus is active, sending the cortex images, sounds, and other sensations that fill our dreams. 
Is there anything reverse psychology isn’t good for? In this case, it may alleviate excessive sleep anxiety. A small study conducted at the University of Glasgow found that sleep-onset insomniacs who were instructed to lay in bed and try to stay awake with their eyes open fell asleep quicker than participants told to fall asleep without this “paradoxical intention” (PI). Participants in the PI group fell asleep easier and showed less sleep performance anxiety.
The most important thing is taking that time off—it’s more conducive to your productivity. A lot of times people think they can like fight through and push harder and harder and harder to get better results, but sleep can give you that, too. When you transition in and out of sleep, your brain produces theta waves, which help you think more divergently. That’s why a lot of times when you wake up from a power nap or from sleeping, you’ll be able to solve that intractable problem that you couldn’t earlier in the day. That’s one of the reasons I think taking a break—whether it’s meditation or nap—during that circadian dip can be much more conducive to productivity.
Try “belly breathing.” Controlled, deep breathing is simply a way to direct your mind away from thoughts that might keep you awake. If you find your mind racing as you lie down to go to sleep, place a hand on your belly and breathe in deeply through your nose — so deeply that can feel the air filling your abdomen. Hold it for a couple of seconds, and then breathe out through your mouth. Breathe mindfully like this for a few minutes, just trying to focus your attention on the rising and falling of your belly as you inhale and exhale. If your mind starts to wander, just bring it back to your breathing. The more often you practice this relaxation technique, the easier and more effective it will be.