Looking for nausea advice.

So I have a history of feeling nauseous with no known reason. My doctor can't explain why. I haven't thrown up for years, but I get really nauseous randomly every month. I could go a month with nothing and then the next month I could be nauseous for days. Anyone have some tips on how to help? Foods that could help or if exercise could? My nausea medication helps to an extent but the side effects are dizziness and headaches and no one likes that especially combined. But I am just looking for some advice on what could help the nausea go away or not be as bad.