Horrific sleep issues

I get HORRIFIC sensations when trying to sleep. Brain feels like its dying or like its intoxicated, it feels like its being poisoned or it shutting down, like its liquidifying into itself or drowning. It feels like i am slipping into a coma or into death, not regular sleep. The sensations are unbearable, they 100% feel like i will die and not fall asleep. Sometimes they stop, when I get up and start doing something, but a weird pressure pulling like sensation in the back of the head lingers. Anyone gets this?