I had this the first week of the diet. I remember the pain so well. Afterwards I felt like, well at least I have an idea of what child birth is like now! hehe
I took fibre 89 ever since and only had the problem again 1 time when I forgot to take it.
Anyways, I hope you feel better soon, been there, had that pain and it was not an experience I'd want anyone to have.
Hugs, Gemma