It is so hard to struggle for so long and not feel like you have any answers or possibilities.
Not all T's are created the same... do you know what kind of therapy your other T's used? T's with different training and orientations have different things to offer. I have discovered that I could not get all my healing needs met by just one T. I worked with a CBT until the dangerous behaviors were under control, a family systems therapist when relationships were the main issue... They all have value just diferent ones for different things. Have your past T's been "warm fuzzy" or "directive"? a change in T personality can help too. If you can try to be open to out of the box kinds of options... I am working with a massage therapist/body worker with a lot of training as a T who is most helpful with my depression.
Meds are a rather random art not a hard core science... and even when you finally get them right. I am 33 and have been on this journey 15 years... One step foreward, two steps back. As some things have gotten better other things have come up to take their place and the work begins again. I know that this can sound discouraging but it is all progress!
Long story short... Progress is slow, feels crappy and often feels like you are moving backwards.
And sometimes "pitty parties" are OK... as long as they aren't all the time. Take time to heal, hang in there and keep trying.