First, WELCOME to PC!!!!
I think whenever there is a change in meds, at least for me, I become very apprehensive. I think how your feeling is normal. We get so use to a regimen that too us feels "functional" My meds have been changed several times and I foresee it happening off and on while I go through my therapy. I think the fact you "stick it out" when you have some of the SE's when starting something new is great because it is so easy to say, forget this, I feel worse. Sounds like you have been on the same meds for a while and maybe you are so used to them at this point they may not be as effective?
HUGS
Cher