I know exactly what you mean about a possible diagnosis being good news -- the best day of my life was when I was diagnosed with type 1 diabetes and started on insulin. Six injections a day sucks, but it's a heck of a lot better than sleeping 12-14 hours a day and being permanently dehydrated.
I don't mean to be discouraging, but I know someone with Celiac, and it's harder to control than you might imagine. Cross-contamination of gluten is a serious concern, and very few restaurants really understand the risk, so it makes it difficult to eat out even if what you order does not have gluten as an ingredient. If it does turn out to be Celiac, just be very careful until you get a handle on what's safe and what isn't. You'd be surprised what all has gluten in it. "Natural flavors" can even mean gluten in some cases.
Nevertheless, I'm glad to hear you might have a diagnosis.
I have some idea of what it's like because I spent a week and a half trying to follow the gluten-free diet before seeing the gastroenterologist. The first 4-5 days felt like pure deprivation, but after I stocked up on some basic "raw materials" such as meats, fish and raw veggies, things got a lot easier, and I was actually enjoying what I was eating. It helped that we opened up the backyard grill that week too. Of course I didn't dine out (or have takeout) a single time during that period, which my wife was not too thrilled about.
If it turns out that I really do have Celiac, I think the hardest part about it will probably be not being able to go out to dinner easily. In the beginning I'll want to do as you suggested- play it safe until I know how seriously I react to the cross-contamination that is likely in restaurants. Some people can order a burger, throw away the bun and eat the hamburger patty, while other people would be sick for days from such a stunt; I have no idea how it'll affect me until I actually start feeling better.
Good luck!