Of Wants and Needs

Yet again, I fail to ascertain the boundary between my wants and needs.
Right now I want a pizza. A gigantic pizza with enough cheese to clog the arteries of an elephant, beef/chicken, and pineapple, at the very least. And I want one from a fast-food chain, which makes it deliciously unhealthier and me fatter. I want that pizza with spaghetti and meatball, with extra tomato sauce and meatballs. And I want those with two sweet and spicy grilled chicken wings.
And what do I need? To eat less junk like that and more organic, healthy, detoxifying food of course. That goes without saying. But most of all I really, really, REALLY need to study. PRONTO. And what happens? I get a major migraine instead, and an abyss of dark depression.
I need to get closer to God. NOW.