Re: differance between IBS and a serios problem?
I know how frustrating it can be, but firstly, if the pelvic pain is new, I think you ought to get it checked out. As I said, it could be that you have a PID or something such as endometriosis that needs investigating.
As for the IBS, unfortunately, if you have had all the blood tests done and further scans and investigations of your belly and bowels, then the only diagnosis that can be arrived at is IBS. It is a diagnosis that is done by eliminating other more serious diseases, so you have to tell yourself, that at least you do not have anything more serious however bad your stomach pains maybe.
The reason for your belly aches will probably have an emotional or stress element and could also be allergy based, so you need to find a good doc who will understand your symptoms and what you are going through and can work with you at finding you the best meds to help your symptoms. I would also suggest that you try all the alternative medications. A lot of people on these boards find them very helpful, including myself.
Alternatives include diet modification, Metamucil, Acidophilis caps, sometimes flax seed oil, pepermint tea, calcium and magnesium supplements if you have diarrhea, homeopathic remedies and acupuncture. Also try some meditation to reduce your stress levels.
I know that it is frustrating, but in the end, I think you have to accept your problem and then start to find remedies that will work for you to keep it under control.
Personally, I use homeopathic remedies and acupuncture, acidophilis and metamucil and most of the time my stomach is good.
Hope this helps and don't despair, you are not alone.