Oh I know just how you feel. I had a bad reaction to a high blood pressure medicine when my BP spiked the second night. Thought my heart would bust out of my chest and I had a horrible migrane. Then a week after surgery I got some kind of bug and lost 10 lbs in one week. Not a great experience. But, you will feel better one day at a time.
Eat well, at least 25 grams of protein with each meal and 2 healthy snacks and lots of green leaf vegetables. You don't really start start to heal until about the third week really. You are just recovering the shock to your body, clearing out the anestetic, and getting back on your feet those first couple of weeks. You just had a very major surgery, this is going to take time to heal. But how wonderful our bodies are. By 4 months it dawned on me that, hey, I'm back to my old self! Better actually in that I went from full time couch potato and 25 lbs overweight, to excercising daily and losing that 25 lbs.
Drink plenty of water if you can, or ginger ale, 7 Up. Non diet! That aspertaine is nasty stuff. Sweeten with Stevia.
Best wishes, congratulations on your donation, and hope you feel better soon.