unexplainable intestinal attacks every few months

Since I was a teenager I have been suffering from severe stomachpain every few months. 

Actually, it is not my stomach, it's the area under my belly button, so i guess my small intestine. 

The attacks usually come up in the early evening or at night, starting with an annoying cramping pain (feels like mild contractions during labor), getting worse and worse until i dont know anymore how to sit or lay down. Standing is out of the question. Every position hurts. I can compare it best with contractions during labour, coz breathing gets difficult, i get hot and then cold again, goosebumps all over, sweating like crazy. the cramps are so bad i feel like throwing up, but this only really happened once. i almost faint (i see stars flickering) and can do nothing, only hope it will pass soon. The severe pain lasts for a few hours (4-6) and then fades out slowly. After that I have a sore feeling in my stomach (under my bellybutton everything seems swollen and inflammated) and this feeling lasts for a few days. It's like my intestines have turned into a swollen ball, that i feel with every step i take. When I was younger I got these attacks quite often, let's say once every 2 months, but now (im 36) i get them about twice a year. The last time was 2 days ago. The attack was so bad i got a migraine attack from it and a fever (38deg C) as well. Last year i was pregnant and I got 2 of these cramp attacks during my pregnancy. The first time when i was 10 weeks, and the last time when i was close to my due date. The cramps set off labour. i can tell u that i was exhausted even BEFORE labour started. +_+

When i was a teenager my doctor couldnt find anything, and 2 years ago i decided to go for a colonoscopy and gastroscopy. Result: everything perfectly normal. My doctor here suggested to use Nexium, and Tramadol. When i searched the net I found that these medicines need to be taken continuously. But since the attacks only happen twice a year or so I don't want to take medicines for it every day when i feel perfectly normal. I have been noticing the food I had before the attacks, and it's always something different, and always food I eat regularly, so i don't think that can be the cause. Could it be stress that triggered the attack? I had a big argument in the family a few days ago (2 days before the attack) that caused me sleepless nights), and the time before (when i was about to give birth) I was stressed as well since the doctor had just told me i'd probably need a c-section which i absolutely didnt want. I got the attack the day after my gynaecologist told me this. A friend of mine who is a doctor told me it could be porphyria, but i doubt that, cause that is very rare. Although i have to say that some of the previous attacks happened after i had taken some medicines that could trigger a porphyria attack. 

I wish i knew what was wrong with me, so i could take preventive measures... coz the pain is very bad (almost as bad as giving birth) and destroys me for 2 to 3 days. I don't know what medicines are best for me, i 'd like to have something that helps immediately to stop the cramps... now i only take buscopan (doesnt help) and a 1000mg paracetamol tablet. A hot pack on my tummy also brings comfort.  I find a lot on the net about stomach problems, but most of the patients have trouble all the time. For me it's really just 2 or 3 times per year. Does anyone recognize this?