Shelly, from your other recent posting I counted five (myself included) who deal with diarrhea on a regular and daily basis; that's only on this little board. I was going up to 30 times a day, every day, for months and months, lost something ridiculous like 25 pounds...what a mess. I lived on Pedialyte and chicken broth for a while. So I know this is hard for you, as it is for everyone, and it will take time for you to adjust - but you will! I think the hardest part for you is feeling like there is something the docs missed and you are riddled with anxiety about that. The good news is, they haven't missed anything. If your extensive testing has revealed no abnormalities, that should help you feel reassured.
By the way, I am 27 and a lot of people on this board are in the same age bracket. The 20's are a common time for gastrointestinal ridiculousness to rear its ugly head.
I would recommend visiting a nutritionist if you are concerned about losing weight and your food intake. It could be your acid reflux causing the nausea that makes it difficult to eat, in addition to feelings of anxiety. Have you been on the GERD forum yet? They may have some ideas about how to decrease the nausea. I am taking a nutrition class right now in preparation for medical school and I can't tell you how much I've learned about proper nutrition. In the meantime, try some liquid supplements like lactose-free Ensure or even Carnation Instant Breakfast (made with soy or rice milk if you're lactose-sensitive) to get some nutrients in.
You'll get through it. Promise.