Jules,
Sorry to hear about your situation. I was able to get a good decade or so out of zoloft, but began having problems about three years ago at age 25.
I am not very well-versed on neurotransmitter involvement, but I can say that I have symptoms of both hypothyroid and HPA dysregulation (which, of course, could indicate several other problems as well). I originally had a flat-lining salivary cortisol curve, but it rebounded after I ditched a low-carb diet I was on at the time. Since then, it has gone too far in the opposite direction (high in-range all day and out-of-range at night).
I thought the HC was helping, but I fear I spoke too soon. Having divided and increased the doses I can barely tell a difference between the hour before and the hour after my dose. This is not very different from normal for me.
Can I ask how long and what your dose of HC was before you weaned? It seems like it may have been helping. Would you consider going back on it or is it not worth it to you?