What Causes Muscle Spasms All Over Body?

I've been having severe muscle spasms all over my body, hands, feet, hips, back, neck - just all over, yesterday, my body cramped up and I almost passed out - room got white, then got chills, and it was 100 degrees outside... New meds were started about a 2 weeks ago for high blood pressure.. but the cramping was actually prior to this - its only gotten 100% worse... what could be wrong?