I went through a 6-month crisis because I was unable to source clean cannabis. Off and on, I would run into contaminated cannabis. Bad weeks I would be in and out of the bath 6-8 times a day or more. I have pain, seizure, autism and other issues so my cannabis use is constant. The issues stop when I have clean cannabis.
The hospital will have anti nausea meds which will help reduce your nausea. Eat cayenne and ginger with your foods. Have them test you for H.Pylori and get a treatment going.
Eat a LOT of yogurt. Find a plain version of Kombucha and drink a quart a day. Make your own (it's easy, lots of tutorials on the web) from tea, sugar and a bottle of plain kombucha. You can order a scoby online if you're unable to find a local bottle of kombucha.
Basically up your intake of pro-biotics significantly. It'll help.