After a couple of months on this drug, I have begun to experience...

After a couple of months on this drug, I have begun to experience a weird feeling while sleeping, especially on my side. It feels as though there are vibrations in my head which in my sleep I attribute to having left the washing machine on underneath me downstairs. Of course, this is an illusion. The experience wakes me up, then I feel my heart beating faster (maybe anxiety?). when I swallow a few times and turn over in bed, the feeling goes away, but it is very disconcerting.