Straight up? Opioids.
Google CWE codeine (hopefully you have no tolerance), there is a way to extract codeine from the paracetamol then either swallow or plug the solution up your ass (literally), you have a lesser chance of vomiting.
You can do the pharmacy shop, so go to as many pharmacies as possible and ask for co-codamol. If it's a male they won't care, if female say it's for your girlfriend who uses it monthly, they will know what you mean.
If you need help with deciding to ctb, I'm not they guy you want lol
I wish you peace.