Educating patients symptoms and conditions

I came home from work and opened my new bottle of Niaspan er 500mg. It was late and my wife was asleep. I read the bottle and it said take 2 tablets before bed with food. I did and about 4 hours later, my entire body was on FIRE and my hair felt like needles pinching my skin when I moved. I can deal with a hot flash or flushing but I was literally RED hot to touch, forget the feeling that I was having a heart attack or stroke.
I am only 41 years old in good health and a little low good cholesterol. I tried again few days later with one pill(after my wife had a good laughed) and experience the same nightmare. No hot flash, I was BURNING RED and my hairs were needles pinching my skin as I put ice packs around my neck.
I understand this is just a form of vitamin B-3??? Has anyone tried some form of herbal version of a B-vitamin?? Has anyone tried to take during the daytime????

I am a female and was diagnosed with Hashimoto's three years ago (looking at old childhood photos I've probably had this all my life) and have taken Levoxyl and Synthroid in escalating doses over time. Initially 25mcg for about a year and that was the endo plan until bloodwork indicated a need for more. I quit taking it after a year as it seemed I was gaining weight. After a few months went to a different endo and he started the treatment again with 25 (I weighed 160 at the time) and now has worked it to 100mcg (I now weigh 178!!!). I thought that with the higher dose I would have more of a weight loss effect (definitely not weight gain) and thought I'd have more energy, better brain function and happier outlook. I am experiencing the complete opposite. The last time I visited the endo and he looked at my weight gain he just said to "stop it". I work out almost every day for 45 minutes to 2 hours, have a job that at times requires arduous work, I eat a very healthy diet full of fiber, low in fat, low in carbs. I'm always hungry and feel like eating to make up for a lack of energy. I come home from work exhausted. This isn't living. I've had it with the Synthroid and any form of T-4 alone. I'm going to see a natural healthcare professional to try Armour because none of the medical doctors I've seen will prescribe it or synthetic T-3.