Hi
I too have the same problems with meds where they will work for a period of time and then things get really bad again and a med change is needed.
Iv'e been on most meds but a few months ago my pdoc tried me on a really old AD, anafranil I think it's called. This med has been one of the best for me so far and I wish I had been tried on it sooner but due to it being an older med if one was to o/d on it it could be fatal and due to my o/d'ing in the past no one has trusted me enough to try it..
Unfortunately there are so many meds out there and what helps one may not help another.
Maybe it might be an idea to write down the helpful med you have been on in the past if you can remember them and note which group of meds they are from... maybe trying a different med from a group that has been helpful will be good for you? or if there is a group you have never tried then that may be an option too?
Talk to your prescribing dr though and see how you go. Good luck and hang in there