Hey Gaz-
I do think coming off of your medication at this point would be a bad idea. Recently, I was contemplating discontinuing my meds. While this is something I still plan to try, it would probably be unwise to make a drastic change like that especially during the initial period of depression over a mixed episodic state.
I've felt the same feelings, and usually experience mixed episodes before getting to full blown depression after manical bursts. It's probably just a natural response to avoid the depression. However, for me, it has never worked because I cannot hide the fact at some point that I'm depressed and no longer care what anyone thinks. Also if you quit your meds, it may take a long time to recover from a depression. It took me about 9 months in the past without medication and now about 2-3 months.
It's important to remember that you might feel this urge because of the state you're in. To control bipolar effectively, its good to remember that things may only be changing within your mind and to make decisions contrary to what you might feel is best.
-D