Blackouts and loss of body functions

I am a 60 year old male with history of 5 spinal surgeries resulting in replacement of 2 cervical disc and 1 lumbar disc. I have really bad degenerative disc disease and just had a spinal stimulator put in 3 weeks ago. I also just had a total left hip replacement and a left shoulder replacement and a double hernia repair since last thanksgiving. I am still experiencing really bad pain in these areas as well as in my lower back, particularly on the left side, radiating up to midway of my back. My main concern now is I am still experiencing something no one can diagnose. The pain all over my body is debilitating and I have had episodes of blacking out and going into mild seizures. It starts with a very hot sensation in my chest that starts to slowly radiate over my entire body, causing me to sweat profusely, even outside in the winter. My arms go completely useless and when the hot sensation gets up to my head, I start to get tunnel vision and can blackout and go into seizures. I can't hold my head up and I can't talk when this happens, and I feel like a limp dishrag. I have learned to get cold rags over my head when this starts and it seems to keep me from passing out. Now I am getting a hot tingling sensation in my legs that radiates up to my head. It comes on quick and I have to get down to the floor immediately or I will pass out. Does anyone out there have any idea what could be causing this? I am also bipolar and have carotid artery disease. I am constantly fatigued to the point of not being able to get out of bed at times. I used to walk 10-12 miles per day on the job but had to quit work because of my condition. I'm scared to try and drive any more.