I have known of this. I think you could have reservations about taking testosterone and those negative thoughts are manifesting themselves in the form of a stress reaction.
Kinda of like this: you have a fast car and take it up to 120mph. Afterwards you have a stress reaction from the danger, thought of a ticket or just plain having an adrenaline rush. Could you be having some sort of adrenal ramp you identify as a panic attack?
My buddy was clean and sober, took one injection of test and relapsed on booze, he never was able to stay sober going on 20 years. He told me as soon as he did the injection he "started freaking the fuck out".
Are you by chance in recovery?
This definitely something to think about.
Something else to ponder. Is this TRT self-administered or through a prescription? If this is not through a doctor, your anxiety could be caused from the fact you are doing something technically illegal. Even if it is through a prescription, some feel like they are cheating at life.
There is also the social stigma, though not as bad as it used to be, about being on testosterone. I hear it all the time from my wife, because she gets asked by people if I use steroids. She just says, no. I told her she doesn't need to lie and can tell them I am on TRT, but even she says she doesn't want to tell them that, as she thinks that is a gray area. We have been married 25 years and I have been on gear almost all of it (never hid a cycle from her) and she still tries to hide it.