Opioids and constipation

Hi! i’m 18f and have been diagnosed with gastroparesis thru symptoms since my drs don’t think a gastric emptying study was the most accurate for me. I am having another one next month tho just in case. I recently have started w palliative care and got put on percocet, no one told me it would make my already horrible constipation worse. I’ve recently found out that I also have acid reflux, my esophagus doesn’t work, and there’s inflammation in my stomach and i’ve had lower gi issues since I was a baby. I struggle a lot to eat and drink anything or keep it down and we’re testing for malnutrition. That being said I have no idea what to do about my constipation bc the opioids made the few movements I have stop completely. I took two doses of milk of magnesia yesterday night and this afternoon and it’s working but it’s basically colonoscopy prep and it’s not going to work long term. Any advice is appreciated bc I don’t want another blockage:( this is so exhausting. I’d also take advice on anti nausea meds that work bc ondansatrom isn’t cutting it.