I had similar digestion problems, although I don't have the diverticulosis. Two suggestions: You really need to see a nutritionist to find out how you need to be eating. If you aren't eating any fruit or vegetables, your intestines definitely will not be happy. It sounds like you are on your way to malnutrition, which can cause all sorts of problems in your body. Ask your doctor if s/he can refer you to a good nutritionist.
Also, there is a lab called Metametrix in GA that does a complete GI analysis. It is very informative as to what is happening in your gut. If your doctor is willing to order it, your insurance should cover it. I paid with a credit card up front (it is half price w/ prepay), and then my insurance reimbursed me about 90%. It was worth it! I did it again 3 months later to see my improvement, and I will do it at least one more time. You would need to get a test kit from them.
It shows stomach bacteria, parasites, yeast levels, balance of good bacteria, signs of malabsorption, and Ph level (too high can cause a bad smell). I had similar symptoms that you describe and I ended up on medications for yeast & parasites & h.pylori, supplements called Intestimax and ButyrEn (both quite helpful for me), and high quality probiotics to help restore balance in the intestines (Klaire Labs Complete).
I hope this is helpful! I know how miserable digestion problems can be.
First off DO NOT WORRY about the reddish brown color. My son, as a baby, **** green every time he drank grape koolaid. #2 (haha no pun intended) everybody stinks! EVERYBODY. Some times I think stink real bad other times I actually think it smells pleasant, (I get real attracted want to weigh it, name it, send out announcements)