Hi Barbara,
I had my left hip done on Dec 3 and I experienced all of what you are describing, at different intensities and intervals - but all the same symptoms. I didn't feel like eating much and knew I really needed to so that my strength would return; I had some low grade nausea, that believe it or not felt better if I would eat something; I had those weird jerks too - bizarre!; and just a few nights ago I had what must have been a night sweat. I woke up drenched, I didn't feel hot or cold - but dripping wet. I panicked and checked my temp immediately. I was terrified I had an infection, but everything was/is just fine.
I am pretty sure all of these symptoms result from the anesthesia and other drugs as well as (I like how Pat put it) our bodies have been invaded and are not happy. I understand your distress. I had read the information posted on this site prior to my surgery and knew that freaky things would happen, but when it was happening to me I was still alarmed.
Thankfully we have each other. There were several folks helping settle me down in the last few days.
I would guess you already feeling better and will continue to do so.
Thanks for posting, makes me feel better knowing I am not alone!
Karen