Diet change and side affects??

A week ago i started the slimming world diet which consists of green days (carbs, rices etc.) and original days (meats, fish, poultry etc). As recommended for at least a couple of weeks I have been alternating each day with green and 'red' days. I have found this diet is a very good way of eating healthily and all the food that i am eating is very nutricious but i am experiencing some unwanted side affects. I do understand that this can be quite a high fibre diet and i am not going to loo as regular but not that bad but I have noticed that when i pass wind it smells really bad and this seems to be since ive started this diet. In the last day I have noticed a pain that seems like a stitch in my side and im worried that my insides could be getting all messed up. Can anyone advise if they have had similar symptoms on a diet and do you just persevere or is it worth stopping altogether.

Any help would be much appreciated.

Lou