What Causes Excess Of Perspiration All Over Body?

Hi! I am 56 years old, and am disabled with degenerative disk disease and Fibromyalgia, I have had 5 spinal surgergies and am on a lot of medications. I know some of these meds cause sweating, however I sweat so bad it is not only embarrassing but at night I have to get up 2 or 3 times just to change my bedding because it is soaking wet. I was wondering, since I drink quite a bit of Diet Coke if this might be helping to cause my problem. Please help me I lose sleep over this and am always tired just from having to get up at night because I am soaked in sweat, and this happens every night.

Thank you.