Horrible reaction to miralax post op, anyone have a clue ?

Per my surgeons recommendation I used benefiber and colace postoperatively for days and neither was doing **** for me (literally). Last night I decided to take things into my own hands and took a serving of miralax. Within half an hour I was getting intense headache/vertigo/light headedness (some combination of them it was hard to describe) my whole body was shaking on an extreme level and my teeth were chattering an insane amount so much that I had to bite down on a blanket. Shortly after I got extreme nausea and major dryheaving (could have sworn I was going to vomit but ultimately didnt)

Eventually I suffered enough and was able to fall asleep. I was extremely close to going to the emergency room.

Im going to discuss this with my surgeon at my prexisting appointment next week, but does anyone have any idea what this could have been ? Im just speculating that maybe because my stomach is so small that when I drank the miralax it didnt end up getting to where it needed to go which could have caused the stomach pain and nauseous but the rest im clueless on.

And on a side note yes it was thanksgiving, but I stuck to my diet 100% which consists of the exact same things everyday so no thanksgiving cheating was involved with causing this.

Thanks to anyone for reading my jumbled mess !