Listening to music on headphones on full blast and either staring outside the window or completely shutting my eyes reduces the nausea and sometimes I don't need to take medication. You could try that.

As for the near misses, take care dude. It is better to be safe than sorry. Most of the cab drivers I have encountered till now were rash drivers but fortunately nothing has happened so far. Almost all of my cab rides end up with me being annoyed or them getting a 1 star rating and sometimes both.