Re: Candida? Parasite? I'm going insane.
OK, so there's all your problems right there. That stress is causing you to have anxiety symptoms (which you mainly feel in your stomach and bowels area -- just like if you're about to compete in some athletic event and feel butterflies in your stomach and have to take a dump right before it!).
And you're actually feeding this anxiety by your low carb/high protein & fat "Paleo" diet. Big no no. When you're stressed you need more carbs for fuel and
Sugar for your brain. It's like your car running at a higher RPM cause your stuck on a long uphill and you're burning up fuel faster than usual.
Just stay away from refined sugars (as you've already done), any stimulants (that's the real evil in things like Red Bull), and too much protein and fat (too much fat is probably the biggest killer).
Read about the 80-10-10 diet (80% carbs/10% protein/10% fats) and go more in that direction even if you have no wish to go vegetarian or raw food. Also read about the 'Starch Solution' by Dr. John McDougall.
For your stress, I've found the technique called "Faster EFT" works wonders. There's a howto thread about it in the Stress/EFT section here, or you can learn how to do it free on youtube.