It's a normal part of the illness to think we don't need the meds anymore. I have done the exact same thing. Try something different. Meds work differently for different people. I've had really good luck with Lamictal. I hope you find something that evens you out and makes you stable.

I'm pretty stable right now (after a two month depression) but I'm not very productive. oh well, my thoughts are not crazy so I'll take a messy house and cluttered desk to delusional depressed thoughts.

Hang in there.