As my gastroenterologist once said, "Stop examining your poop every day."
Your poop can be a rainbow of colors and consistencies throughout the week depending on what you eat, how much stress you're under, how much exercise/water you're getting, etc. I've literally gone from dark brown to yellow to green in the same day thanks to anxiety. Gastros are concerned with consistent changes (i.e. more than a week) in color or consistency, or extreme color changes (e.g. chalk white, black & smelly, etc.).
Btw - yellowish-tan/brown is a TOTALLY normal color.