I have been drinking Rockstar for quite a few years. I now have stomach issues. I have not had one in about 2 weeks and some of the stomach issues have subsided, bit the rush to bathroom has not. I probably have a movement 4-6 times a day. I stopped. It is a miserable gurgling feeling.
If Rockstar is anything like soda pop, there is added acid-based ingredients that can do damage to your stomach and other digestive organs. I just stopped drinking Dr. Pepper recently and I am feeling much better; my stomach doesn't feel queasy, but I have noticed going to the bathroom moreso in the mornings. I think it might be the coffee. It might be the next thing to go! The gurgling in your stomach sounds like you may need to take some probiotics to help balance your intestinal flora. It should help with re-doing the damage from the Rockstar as well.