Pain - Could it be IBS? Appendicitis? Help!

Let me start off by saying that I am a worry wart. This may be contributing to my symptoms, but here is my problem...

Back in March of this year, I was diagnosed with Giardiasis. My gastroenterologist put me on powerful antibiotics for 10 days to get rid of the parasite infection.  I have had intestinal problems ever since. My problems started in February when I was having a lot of abdominal pain, loss of appetite, and yellowy stools. This all was due to the Giardiasis. Another thing that started to happen was I was getting occasional lower back pain. Ever since then, my stools have returned to a normal color, but they are not completely formed, and I have pains in my lower right abdomen, as well as under my belly button. The lower right pain is not constant, and seems to be associated with gas. The pain under my belly button tends to go away after a bowel movement. My back/side pain is usually all of the time. It isn't intense, I can deal with it, but it is still there. I can press on my abdomen and feel no pain.

Let me also add that I am overweight, so I was thinking that could be possible for my back pain as well, but it is always in the same place.

Any ideas?

Prior to my colon cancer, etc. and my colon surgeries, my husband had an emergency appendectomy. It was our immediate family's first experience with major surgery (our children were 2nd and 5th graders then). My husband initially thought it was a bad case of heartburn. He was treating it like he usually did but nothing would work. I went to sleep only to wake up in the middle of the night, the entire first floor's lights were on and he was pacing the floor. He was miserable. I asked what he needed, should I run to the 24 hour grocery/pharmacy for OTC meds but he said he had them, none were working. Other things such as walking, eating one piece of bread, drinking a full glass of water, nothing was relieving the indigestion or heartburn. By 7 am, he called our Internist's office. They gave him an appt., as soon as they opened, 8 am. They did a urine test and sent him promptly to the ER, saying his appendix would likely come out.

Long story shot, he was fine, we caught it in time so it wasn't infected. But it needed to come out.

Later we both realized as parents of young children, never to ignore a stomach ache or indigestion/heartburn. If in severe discomfort that isn't relieved by the usual OTC meds, etc. then call your doctor ASAP. My Internist said he should have gone to the ER the evening before, when it all started. We were lucky it didn't rupture.

Strictly from a layman's point of view, IBS is chronic and appendicitis is acute. IBS might resolve itself and subside, with my husband's appendicitis it never got better but only worse.