Damn anon, nice death collection you've assembled there for yourself. That quantity of fentanyl alone should kill you, the booze and xanax will just be a reassuring insurance policy. Definitely take email all and you won't be around much longer, just make sure you're alone.
Anti-emetic? In terms of both effectiveness and ease of availability, it'd be probably diphenhydramine aka benadryl. I use it occasionally when recreational opiate usage makes me queasy.
Good luck anon, I hope you soon find release.