What Causes Excessive Flatulence And Constipation?

For the last couple of weeks my stomach has been so noisy with or without food, plus excessive foul smelling wind, something which I have never suffered from before. I do get very constipated, but thats always been the norm for me. I also suffer from frequent water infections. I am female and 63yrs old. What can I take to avoid this embarrassing problem? Thank you.