How long til i see symptoms?

I just finished my period last Wednesday, yet i feel like im gettin it again or something. The cravings are awful. I dont usually eat much and when i do its usually clean healthy foods but since Saturday all i want is chips, n cake etc. And a lot of it!!! O and hoagies! And ive gone from super energetic to i dont even wanna leave my bed. Wat is going on?!?!?