I am so sorry to hear you are going through this. My sister starts chemotherapy tomorrow. Someone she spoke to today (non medic but whose wife went through breast cancer last year) told my sister that if she feels any medication she’s given isn’t helping her with anything - especially sickness - to ask for a different / higher dosage or a different medication.
I don’t have any experience if this yet. I hope you can get something to help you feel better soon. Thinking of you and sending much love.