I'm trying to loose weight, but am most hunry after 8pm why? And how can I stop from eating after then & ruining my caloric intake for the day?

Drink tea. A mug of ginger or peppermint tea with a little stevia for sweetness can take the edge off the cravings. Make sure you eat a good dinner which includes healthy fats and protein. That will keep your blood sugar levels steady until bedtime.
Discipline & support. Eating after 8pm is a weight gainer! do you not eat or eat poorly all day then feel starved when you get home? Coming to the table starving you can't feel satiated soon enough to stop, so you overeat. Do you watch tv or get on the computer & snack your way into the evening? The best thing one can do to stop that kind of eating - eat right during the day, at home have a meal & "do" something active.