Alter (and Eq)- I have no help with the nausea thing, (and do wish you luck getting to the bottom of it!) but with the dead foot- I was having the same issue and discussed it with my orthopedic surgeon today. She (actually the PA) said that intermittent numbness is usually a pressure issue rather than a nerve issue (this was good to hear, because I’m having severe spinal issues).
So anyway, I got these great stirrups and my foot doesn’t go numb anymore!
http://www.vtosaddlery.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=EWTSI
They also come in a jointed version. Good luck with it all! I have been getting amazing feedback and help from my physical therapist with “random bizarre pain stuff”- hopefully you’ll get help somewhere too!