When the time comes a good dr can make you relaxed and even asleep regardless of what kinds of personal problems you may have with something like benadryl. Just relax. But before you do anything like that again explain the situation. Most drs are compassionate about patients' anxiety. If the dr doesn't seem to care then I would find another dr. You're the customer. His job is to get the procedures done while keeping you safe. Drs are not supposed to make moral judgements, only provide quality medical care. Good luck and God bless.
I am not a dr. My statements are based on years of experience and related education. Consult with the professional of your choice regarding matters of concern.