scared to take a medical exam

I've been dealing with stomach problems and gastritis for about three years. the thing is, my doctor asked me to take an endoscopy exam and I haven't done it because my OCD makes me so afraid of what I could do or say under the effects of anesthesia. I'm afraid I'm going to start talking about my obsessions, even the ones I haven't shared with anyone, and those are the ones that make me more afraid. anyone else needed to be anesthetized here? what where the effects? I could really use some advice on this issue. thanks.