I think the nauseous OP mentions is of psychological kind...

I think you should sit down and think how and if the meds are helping and if it at all... maybe you need something different. Or maybe if you been medicated for a while and not much results... time to go back to scratch and see the real you...

what you describe can be either self-sabotaging behaviour or your body and mind subconsciously rejecting the treatment. None of these will be solved by just switching to fancier type of lithium, imho.