Is it possible this could be some sort of Circulatory System issue? This 'buzzing/vibrating' feeling you mention.....does it feel like when your feet wake up after falling 'asleep'? That
sorta 'tingling' feeling?

You mentioned low blood pressure and weakness, that's what triggered my questions.

Are your feet cold all the time?

Also, Re: Xanax,....I took that for awhile, and when going off of it, I recall having spasms and very uncomfortable feeling all over..... Not sure what dose you take or how regularly....

Just throwin this out there?