What Causes Increased Appetite And Moody Behavior?

i'm afraid i might be pregnant. my symptoms indicate either pms or pregnancy, but i've never experienced these symptoms with pms before. usually when i have pms i'm moody but other than that, nothing...since i was 12. the last few days, i have been in tears over nothing, and i have been eating everything in sight. my menstrual cycle is so regular that i can almost predict it to the day. i have never experienced any appetite increase as i have in the last few days.