Welcome to the boards. You should definitely be feeling better in terms of the pain. Sometimes the meds have side effects that often make us feel just as miserable as the condition which makes this disease difficult to manage.
The nausea you are feeling is most likely from the flagyl. I found that I had terrible side effects from this med and the doctors decreased me from 500mg to 250mg which I tolerated far better.
Have you had a colonoscopy yet??? Ususally this is done after the infection is under control and inflammation is down....around 4-6 weeks after an infection. Obviously they cannot do this with you until your pain is under control.
Are you being treated by a gastroenerologist?? If not I highly recommend you get an appointment with one ASAP.
Diverticulitis runs rather aggressively in younger people (those under the age of 50). Diverticulosis is the appearance of tics or pouchlike areas within the colon. Alone these will not cause problems....however when food particles become stuck in these pouches due to the bowels not being emptied properly (eg:constipation) or the ingestion of undigestible foods that increase the likelihood of them getting caught in these tics (eg: popcorn, corn, nuts, seeds), they become infected and by the time you feel the pain a large portion of the colon is inflammed/infected. Depending upon how much inflammation there is & how long it has gone untreated...there is a good chance of abcesses or perforation occurring in which the colon leaks into the abdominal cavity. This will be evidenced with increasing pain, fever, chills, and nausea vomitting & diarrhea which will require emergency intervention in a hospital setting.
From what you describe...you are not responding well to the meds. The pain should definitely be letting up and the pain with BM's is not good either. What is your diet??? While the colon is infected/inflammed it needs to have minimal stress or pressure on it. That is why a lo residue diet is necessary to allow for the colon to be minimally working while it heals. That means avoiding high fiber foods such as whole grains, raw fruits & veggies, salads, fatty & spicy foods aand of course anything that is difficult to digest such as corn, nuts, popcorn, seeds etc. This should be for at least 3-4 weeks after an infection. Then it's back to a high fiber diet which will prevent further episodes from occurring. But evenso....some people despite dietary changes and increased fiber in their diets are victims of this disease's aggressive nature and must resort to surgical interventions in order to avoid perforation, sepsis and even death.
I happen to have been one of those lucky people who needed the surgery and have to say that since having the surgery (a colon resection) in which they remove the area of the colon that has the tics and reattach it to the rectum, I haven't had one regret. I had been hospitalized twice for a week each time and been treated 3 more times on back to back meds like yourself over the course of 2 years. When the surgery was first suggested after my second infection I ran the other way. However, having 3 more infections within months of one another I decided that my body was telling me that this was only going to get worse. And so....I had the surgery and haven't had an infection since (that was since May 2004).
You need to call your gastroenterologist & tell him that the pain is not getting any better. If it gets worse or continues to stay the same you need to get to the ER and be further evaluated. Did they at least do a CAT scan or barium enema & bloodwork to rule out an abcess or perforation:??? If they didn't then I strongly recommend you go to the ER and be further evaluated especially since you are not responding well to the meds and you may have micro perforations which can be life threatening. I certainly do not mean to scare you only to inform you that this disease is dangerous if left untreated.
Please post & give us a further update.....Goody