I can tell you a couple of things from my own experience with Effexor. I didn't find it did much for my depression, more accurately, I feel exactly the same depression wise.
For anxiety, it did do something, not nearly enough, but I didn't realize it untill I quit it. But there are a few big anxiety triggers that were totally absent while I was on it. A couple trauma related and one or two I've had forever. Did I personally feel it was worth the side effects of Effexor? No. But that's me.
The other thing I can tell you is that the withdrawal symptoms are quite bad. From what I understand about the possible scope of the discontinuation syndrome, I got off easy.
I had "brain zaps" for about 2 weeks, they were quite debilitating for the first 4-5 days, including some nausea and vertigo.
Fortunately I was spared the emotional and psychological negative rebound symptoms. Some of that was my doing, some of it was luck.
For example, I noticed that during the worst of the withdrawals, I was in almost total control of how I was feeling emotionally. I could either be in good spirits, or suicidally miserable. It was up to me to ensure that I surrounded myself with positive things, otherwise I would easily swing the other way. Once I figured that out it was a fairly simple matter of living in a little bubble of positivity.
The downside and danger of this however is that life is not predictable. This is where the luck came into play.
Nothing bad happened while I was undergoing the withdrawals. No one got sick, hurt, struck by lightning, ect, ect. I managed to pick a time when the world ran smoothly (for once).
The reason I mentioned all of that? I quit cold turkey.
The other thing I have learned from taking just about every drug there is for this sort of thing is that they won't make you happy. They can only make you stable, happiness is up to you. (not what you want to hear, I know.)
But it's not necessarily a bad thing. Finding how to be happy, or at least content with life is a very hard thing to learn, probably the hardest thing to learn, especially for people with PTSD. There is so little reason for us to even look for it. We obsess on the horror, while forgetting the good.
I myself have have had to learn and relearn this same lesson, over and over again. That there is no pill to make it all better. I have to do that.
Why is this a good thing?.... Maybe it isn't, but at least you know where to start. When it's working, it's good. When it isn't, the meds are supposed to help keep you from falling so far down that you can't find your way up again.
Don't give up on it, talk with your doctor, make them understand that you don't feel helped by the current meds regime your taking. Write down what you are feeling from your meds, good and bad. Go through the list with your doctor. Even find out if you can email the list to your doctor ahead of your next visit, so they have a chance to read it, then they can ask you better questions than, "so..... How are you feeling?"
I hope you find something in this small novel I have written helpful. Keeping you in my thoughts.