Hi Bobby
I feel your pain friend, my second year upgrade took about 4 months to complete, at least three of which were due to continued rejections from my supervisor. Firstly, if your writing up a paper then you must be doing alright at least, personally, I'm nowhere near having enough data to write my own publication and I'm 2 months into 3rd year, and have been told I'm progressing fairly well.
My big problem with the whole 2nd year report business was, like you, a lack of clear instruction. At first i did the minimum having not been told what to do, after my boss threw it back at me and basically called me an idiot because she couldn't understand it, i simplified everything and it came out ok. I appreciate this may not be the problem your having. You may simply need to be honest with your boss and say your fed up with her constantly changing things.
If this does not work, I'm unsure what to suggest, it may be that telling your boss that you want to leave may stimulate her into doing something about the problem, though please only use this as the last resort.
Good luck