Scared for my sister, symptoms of anxiety?

I'm hoping someone can help me. I don't know if this is even the right forum but I suspect it might be.

My sister is 24 years old. She's active, thin, in good health overall but she has been having a myriad of symptoms for some time now (not sure exactly how long) that are interfering with her quality of life. She often gets sick after eating (diarrhea, nausea, stomach cramps) and sometimes has no appetite at all. She describes being at work sometimes speaking to her boss or other workers and not being able to concentrate and feeling like she's drifting in and out of conciousness but she never faints or anything. THe drifting feeling is because she feels the stomach problems and pain and can't concentrate. I live far away from her but have recently seen a sample of these symptoms because I spent the weekend with her. She got married Sunday and was a wreck all weekend. Saturday night she woke up sick, feeling nauseous and nervous. She was vomiting and shaking and only slept for about 2 hours that night. The next day she couldn't eat more than a bite of food, not much liquid, and felt weak. She was distracted all day, didn't show much joy when opening gifts people brought for her, and was generally, just sick. Her friend came over and performed acupuncture on her. She had never tried this before but claimed she felt 80% better when it was over. She had an appetite and was able to get through her wedding and reception and even had a good time. She loves her new husband so I don't think it's about not wanting to get married. She has these symptoms at times with less stress as well.

Has anyone had or heard of these types of symptoms resulting from anxiety or depression? She's been to a gastroenterologist who prescribed a colon relaxant. It doesn't help her. It was heartbreaking to see her go through this on what should have been the happiest day of her life. I love her and want her to have a great life. Any suggestions?

Thats a possibility the Colon will get you all tied up in knots making you weak vomit and not eat alot
I have crohns so I too go thru alot with this at many points in my daily life
I would suggesst your sis have some tests done to find out what this is bt I think I would put money on it about the colon to be honest ......Please keep us posted and take care you are so special as her sibling Kudos to you
Lyn
You very well ask some questions just dont duplicate the posts on the crohns Forum as well
Post here often we will be glad to support you and her
Lyn

Thank you all for your thoughtful responses.  I had also thought Crohn's disease might be a possibility.  Do you know if it worsens when under stress (like a wedding weekend).  She has symptoms all the time but seems to be magnified by stress. 

Also, those of you who had spastic colons, what medications helped you?  I think she's on Levbid and says it doesn't help.