Nausea is a common side effect of all opiates, including tramadol.
The best way to deal with it is lay down, drink some ginger ale (I know you've already tried that) and eat a light snack when you consume your tramadol.
Also the good old school first-generation antihistamines are useful: promethazine, diphenhydramine.
Cannabis also has an awesome anti-nausea effect