Something goes wrong with the anesthesia - either too much of something; or it mixes wrong with some medication you are taking; or there's something wrong with the anesthesia itself. Vets know all about it - Doctors NEVER admit to it.
BTW - I notice despite everything, you are weighing yourself.
Teri...I've been thinking about you..you are still in my prayers...I am so sorry that you are having to go thru this.....I will pray that it will all be over soon and you will be stronger and back to yourself!!! Hang in there..you are a wonderful strong person..despite this thing!!!!!! Hugs... And for another take on the BRATT...my dr. always said it was tea and toast..so go figure?? LOL....???