What Causes Flatulence With Bad Odour?

Hello Doctor, I get extremely gassy, where it s very foul smelling like rotten eggs. I do notice it when I have fiber for breakfast such as my every day morning bowl of Mini Wheats and milk. So on top of the gas, when I fart, a piece of tissue comes out. Like a shedding of skin inside. It s very embarrassing and I would like to know what it is or could be causing it. Thank you.