Have Been Using 4 Mg Every 4 Hours Of Xanax

Have been using 4 mg every 4 hours of Xanax for 6 months. I now have constant tremors even bordering on seizures that feel neurological. I also have insomnia because of the tremors. I take 1 xanax at about 2 am along with an ambien and I am able to get about four hours of sleep before the muscle spasms begin again and then I cannot sleep more. My friend thinks the tremors/muscle spasms and seizures when are caused by by the xanax. What is your opinion? I try to stretch out the time between doses and sometimes I go 5 or 6 hours without a dose but it is very hard.