"I won't stop self medicating to in support of my transition to an ego-syntonic biological state until I can entrust a doctor with the responsibility."

There's a couple of things your endo is going to think about tomorrow when you tell them about your DIY meds, but chief among them (in importance to you) is "harm reduction."

Essentially, you obtained and self administered hormones already. You need to confirm to your endo that you have no intention of listening to instructions to discontinue the HRT: tell them you started it without medical supervision because of being in the closet and being unable to ask a person for help, but that you have had an improved relationship to your body after starting hormonal therapy.

At this point the physician has the option of telling you it's a bad idea knowing full well you are not going to listen to them on this issue and they can just enjoy being a spectator when they get your blood work, or reducing the potential for harm by putting you on a supervised HRT regime.

There's likely to be more willingness on your endo's part to accept the necessity of your transition if you are able to talk about phenomenological transition: interacting with people in your chosen gender, having a therapist or a regular relationship with a transgender support group, or even coming to the appointment presenting in your ego-syntonic gender.

I am not a doctor and this is not medical advice. If your endo is not comfortable with transgender patients, replace them: any competent endo can treat the symptoms of diabetes, but only a doctor willing to treat their whole patient can help you get better. Don't settle for a shitty doctor.

You own this. Go get some sleep and go in proud of what you have accomplished tomorrow!