Why am I still sick?!?

Ok so basically about 5 months ago I went to the doctor with pains in my tummy. I had been ignoring them for about 2 months on and off. He told me I had colic, gave me some fibre drinks and I was fine. Now, 5 months on I'm experiencing pains again. Seriously agonising stuff. Everytime I move I get a painful twinge, the pain seems to be mostly under my belly on (when I push down on it). My tummy is really, really swollen. I was throwing up all last night, I don't know whether that's a sign of something wrong, or was it just the pain. I can't really do a number two without trying for at least 10 minutes, and when I do the stool is loose, greasy and really dark. I've noticed my tummy being swollen for at least a week now. I'm wondering could someone tell me what's wrong? Do I not have enough fibre in my diet? Am I eating something I'm allergic to? Could I be a coeliac? Do I need to go to a doctor? Any suggestions would be really appreciated.