H2 blockers side effects

I have been using Pepcid OTC for several months now for GERD and have experienced increased fatique along with waking during the night and not being able to go back to sleep. I was wondering if anyone else has this problem and what I should do about it. I also take Xanax before bed (have done this for about 8 yrs ) and wondered if there is some kind of reaction between these two drugs. My fatique lasts all day along with some mild dizziness and some times a  headache. I cannot tolerate the PPI's because the cause headaches. Any suggestions as to how to handle this problem?