Will entonox be enough to calm me and relieve pain for sigmoidoscopy? extreme anxiety. also told to take valium before i go although seem to be immune

Entonox: Nitrous oxide(entonox) should be plenty to relax you for a procedure. If you're tolerant to valium or similar medications you may require higher dosage than others who aren't used to benzodiazepines, alcohol, etc.

You'll survive, even: If it's awful and the medications are not totally effective, it will be over in a reasonably short time - so you will get through it. If there is time to find a skilled hypnotherapist, that may be an adjunct or alternative to meds. It's a good technique and a skill some are able to learn as self-hypnosis for dealing with medical procedures and/or pain. Consider it for next time if too late now.