I agree with everyone else, Natalie. You are not failing the med; it's failing you.
Quality of Life is very important, especially when considering how long we are on the meds. We're not all the same. What may work for me might not work for you.
Since I'm very sensitive to medications and had my share of rare reactions, 2-4 weeks for a bad side effect like nausea would be all I would allow before I was yelling at the doc. If they had to give me as powerful as an anti-nausea pill that you are on, I would've told the doc I was stopping all my recent meds one at a time to find the trouble maker. But that's just me.
Take care of yourself, natalie.