Shaking uncontrollably HELP

I had a c-section 3 days ago. All went well on my end (baby is having issues). Light bleeding, no infection yet, only on Percocet, Mylicon, Maalox, and a stool softener. Got colostrum out but I'm dry now waiting on milk, I guess. Also got an MMR shot and took a Unisom to help me sleep with baby in NICU 30 mins away and all my fears come true. ANYWAYS, I just woke up to pee and I suddenly became absolutely freezing and shaking severely. Drool everywhere as I tried to beg my hubs to help through the shaking. I was crying from fear. My body was being attacked and I couldn't stop it. Lasted about 5 mins. Anyone else go through this? I've never been so scared for myself before. Please help me understand what attacked me! TYIA.