What can all of my symptoms mean?

I'm eighteen years old and on August 9th, 2010, I started getting intense pain in my stomach. Not my abdominal, my stomach specifically. From there, the pain only worsened. Then, it faded and became intense nausea. I've experienced this every day since and it is now October 13th, 2010. My gastroenterologist is baffled by all of my symptoms. They are all as follows:
1. My red blood cell count is a little high.
2. I'm nauseous no matter what. I'll get hungry and eat, but I am constantly nauseous.
3. For the past two weeks, I've grown constipated. I've never before had this problem.
4. My feet swell and so do my ankles, wrists, hands, and fingers.
5. I bloat whenever I eat anything, no matter how little the amount. My bloating makes me feel even more nauseous.
6. I've had a thirteen pound weight gain in two months even though I've kept up the same diet and exercise program I've always been on.
7. My moods swing terribly - maybe because I'm gaining weight. I don't know.
8. My stomach is hard, but my sides are still soft. I've always been chubby, not fat, but this is getting worse.
9. My menstruation caused the problem to worsen and it was unusually heavy.

Now, before questions of possible pregnancy are asked, I've never had sex in my entire life. The symptoms grew worse during menstruation and then went back to hurting only slightly.

I'm tired of the pain and the nausea, but no one can figure it out. The ultrasound of my pancreas, gallbladder, liver, and right kidney came back normal. All blood tests were normal except for the high red blood cell count. I even had a stool sample to check for abnormalities and it came back normal. I have to have a test on October 15th, 2010 which I believe is called a Hida scan. I do not know what all of this can mean, and my research tells me nothing. Can anyone else help me?

From what I have been told, they are checking me for:
1. Celiac Disease
2. A gallbladder disease.
3. Irritable Bowel Syndrome
4. Possibly endometriosis, but they do not yet know.