I’m supposed to start chemotherapy soon but I just don’t think I can do it.

I have apt of pre existing conditions like migraines, POTS, vertigo and celiac disease. Plus my body is just incredibly sensitive. I just don’t think I’ll be able to handle the side effects. My Drs are like well you do it or you die kinda attitude. my biggest fear on this planet is vomiting (idk why but it is) and anti nausea meds don’t help me much already. I just don’t know what to do. It’s for lymphoma and I’m 22.