Honestly it sounds like you both need space. He needs space to work his own issues out, and you need space because being away from a person should not make you feel like you are "dying inside".

All healthy relationships involve fights at some point. This is because you are different people and bound to disagree on at least one thing. Granted, someone who isn't stable at the moment is going to be more extreme, it doesn't mean that this isn't a normal thing for a relationship.

Insincerity is a tough thing to fight about because it can be the end of a relationship, whether you want it to be or not. If it's not, great, both you and him can laugh about it later. If it is, do you really want to be with someone who thinks you're going to cheat on him?