Why is my mood easily affected by environment?

Pretty much anything can affect how I feel, from what i've eaten to what i listen to the colors surrounding me. Why is that? I can be thinking in certain manner at one second and then take a rapid turn, for example, I can be blue and powerless but then BOOM, i feel as if i could do anything in the ******* world and half a minute later i can feel as if the world was black and white.