Ambien is a fine sleep aid and is non-addictive, but with most OTC medications taken on a daily basis, you eventually build up a tolerence and it will lose its efficacy. Ambien will do NOTHING to help with your anxiety issues. (Unless you want to count the hours it makes you sleep as "anxiety free time") It is also NOT a painkiller, so whatever your gastrointestinal issues are, the Ambien is NOT a factor in either increasing or decreasing those symptoms.
I'm not sure what kind of information you're looking for regarding sedatives and antianxiety medication. If you want general information on what's out there, any web site NOT sponsored by a pharmaceutical company will give you adequate info. If your looking for something "meatier," like comparative reports, I would suggest a trip to the reference section of your library. (Yes, I said the "L" word!) But you can no doubt find that on the Net as well. I just don't happen to know of any specific sites to send you to. A PDR will give you the exact information your doctor uses to prescribe meds for you.
I am hoping that you are seeing a gastroenterologist for your stomach problems. If not, I would humbly suggest your GP recommend one. Since your stomach keeps "telling" your head that something is wrong, it's your stomach that needs a good vetting.
Have you actually been diagnosed with anxiety? Or have you relied on your "introspective work and meditation" to reach certain conclusions?
Alcohol and nicotine are infrequently prescribed for anxiety related issues and I'm glad you discovered their drawbacks.
In my humble and non-medical opinion, I would suggest you see your doctor for a very extensive physical which will hopefully include a visit to the Endoscopy Lap to rule out serious problems with your stomach. Then I would seek out the help of a good therapist, preferrably a psychiatrist/psychologist who can prescribe medications and discuss these issues with him/her.
If you are looking for "chill pills," there are definite reasons you feel you need them. But pills are not the answer. Yes, they will make you feel better, but until, and unless, you get to the root cause of your anxiety, you will only be masking the real problem.
I wish you luck on your search and know that we are always here to lend support.
Peace
Greenlydia