Thanks for the support, guys...
It turns out that the depressive episode that made the PA freak out was more of a random chemical imbalance than directly related to T, as most of you suggested...I started T again with a new endo and I have been feeling much better for the past 2 weeks. For some reason my physical changes have picked up after the 10-day hiatus, so that might be one reason for my better mood, since the slowness of the process usually gets me down.
But who knows? There are so many factors involved in emotional stability. But at least now I realize that I have to get my mental health under control, precisely because it is a separate issue from my transition. Well, not entirely, but I mean that there are some chemical imbalances that T will not solve. And I don't want to run into the problem of being taken off T again just because of misdiagnosing.
I have to find a good regimen for myself, which probably includes medication (thanks Emerson). I know staying sober for a month has also considerably stabilized my mood. The self-destructive trajectory I've been on for the past decade doesn't make much sense anymore now that I am on a path of self-love, so my familiar crutches are just bad habits at this point, and I feel stronger and more able to let them go little by little.
I hope my situation can help others. Transitioning is hard. Being transgender is hard. I still don't understand how "preexisting mental health issues" can be a hindrance to accessing HRT, because I can't imagine how one can be perfectly serene living as a trans person in this society. I'm assuming all transgender folks have dysphoria at the minimum, and that's already such a pain and obviously leads to depression/anxiety etc. My doctor reacted to her misconception that T was causing me harm, when in fact, a. I most probably have an unrelated chemical imbalance b. Transition is hard - not because it is the wrong thing to do, but because it's so difficult and requires a lot of strength. There are so many things involved, so many challenges that are unrelated to T - such as self-acceptance, patience, facing discrimination, etc. - that it's unrealistic to expect us to be 100% peaceful. Or at least for those with a more anxious nature, since anxiety blows things out of proportion...
I guess my point is that transition is hard, and we know that right from the start. The waves that will come in our path are expected, although we can only find the skills to overcome them when they show up because they are new challenges we haven't experienced yet, but these waves in no way make the path less worth it. It's easy to be overwhelmed by the challenges, especially when mental health troubles double their intensity, but we have to stay strong and take some distance, to see that they are only waves and that the sea gets calmer at some point beyond the turbulent waters. I'm just a newbie, and from what I've learned in only 4 months, I can only imagine how much the more experienced guys have learned. But I'm just using this brief respite from the constant fog in my brain to put this out there in case it can help some of those who tend to feel hopeless like I do...