Are you on any acid blocking meds? You should be on Renitidine or Omeprazole, Prilosec or something like that. I take 2- 20mg omeprazone in the morning and 2 again at bedtime.
Your surgery is very recent so peristalasis probably has not really begun yet. The muscles will recover and you will be able to keep things down better in a few months. Yes, elevate your bed and get a wedge. You can order from JC Penney or purchase at a medical supply house. I recommend the 12 ".
I slept in a recliner at about 40 degrees. It took almost a year before I graduated to a 12" wedge in my bed and our bed was up on 2" bricks at the top. The acid really burns, tastes terrible, and is very annoying. My surgeon told me the biggest danger is aspirating stomach contents into the lungs. I did that once.
In our family, we found milk products produce acid. Try using lactaid or cutting out milk for a while and using soy. Although it is very troublesome, don't let it get you down. You will gradually find the foods to avoid, foods that do help and once the peristalasis kicks in the acid will not come up as much. This may sound crazy, but I found that a small amount of banana or peach before retiring helped. Saltine crackers will also absorb the acid and I keep Rolaids Multi-Symptom pills on the nightstand. Even now, 4 years out, I have bouts of GERD now and then, but not enough to be upset about. My doctor gave me a GERD Diet, but I don't follow it. Best wishes as you recover, I'll be praying for you.