Oh, that's right. I forgot about your surgery. I don't know whether some blood banks/blood collection agencies have a waiting period after surgery, but my local blood bank says it's okay as long as you are healed and haven't had a blood transfusion in the last twelve months. There's a whole host of other exclusions, of course. This facility is abiding by general Red Cross guidelines (which is why the people there refused to code me as male), but I don't know how the for-profit blood collection centers are run. Check your local facility.
If you go to a blood collection agency, some are apparently prejudiced against trans people, so be expecting that.
Honestly, I think you should try to get hold of the doctor you saw originally. See if you can at least talk to him on the phone--or, better yet, see him in person ASAP. It's really not good for you to decide for yourself what to do. When I was told to cut my dose in half, I felt trapped. I knew I still had significant depression issues that the clinic was ignoring. I couldn't afford to see my regular GP or my old endo, so the clinic was all I had; but because of scheduling issues, I couldn't even make a follow-up visit with another clinic doctor! But it sounds like you might have better options. If you don't have scheduling issues, then make another appointment as soon as you can get in. If they allow drop-ins, you might even try that.
In the meantime, you might call back and find out precisely WHY they are recommending cold turkey when (1) your first clinic doctor EXPLICITLY instructed you not to stop suddenly, (2) you are worried about the dangers of doing so, and (3) you are perfectly willing to taper/reduce your dose (if, indeed, you are). Having conflicting instructions between two doctors is a real problem that needs addressing.
See that other doctor. In the meantime, get some more specific answers.