Abdominal attacks, severe but infrequent ~

Hi , I'm a 41 yr. old female in very good health and no pre - existing medical conditions.
I have had severe abdominal attacks since I was about 23 years old. They come on with little warning -i have bloating and a mild headache,  and cramping to the point i cant stand up-right. I generally begin vomiting within an hour or so after initial cramping. Sometimes the vomiting will last 4 to 7 hours, then I am completely fine again. The only after issues I have is severe pain for about two days, seemingly  subsiding each hour for the following days.
Generally I will have 4 to 5 attacks per year.

I have tried blood type diet, by eradication of certain foods I thought I had a hold of my issue because for almost a year, I had no attack. Then,,, bam,,, another one. Lasted about 4 hours and then I rejoined a dinner party but just could not stand , due to severe tenderness. The area below my right rib is the tender part and I do get a cramping in my lower back. I have no blood in my stool, I'm very regular and normal in that area.  
I have a very basic diet , I'm vegetarian, and no trigger foods have been found.
Blood test have come back normal - i even asked to be checked for ovarian cancer....( It runs  in my family), upper gi - and lower- normal.,  I have not had a colonoscopy, but I think I should.
My doctor has requested an ultrasound of my abdominal area and pelvis. This will be a cost for me of over a thousand dollars due to insurance does not cover a non-emergency.
The frustrating part is once the episode passes, I do not want to keep perusing because I am constantly told to come while Im in the midst of an attack, last time I tried my dr. Was on vacation, next time I was on an airplane.
I read one story of a guy with similar issues that had a narrowing of the colon,, the article ended at that, so I do not know what he ended up doing.
I would love to hear if anyone out there has similar symptoms and what or how do you do or have you been diagnosed??
Thank you-- Mo

[melondoe]

I have a similar condition.  Every test I take shows infection in my body.  I am usually in the hospital every three months, an they have no answer of what to do.  I pray you will find a answer soon and me to