I've been on birth control for like 2 weeks and i've been loosing weight even though i've been eating normally, is this normal?

No: But not a side effect of the pill. If anything one would expect weight gain unless you are nauseated but you say you are eating normally. If unintentional weight loss continues for a couple more weeks you should go back and see your doctor.

Depends: There are many things that go into gaining or losing weight --- at your age, you are constantly growing, and will until about age 24, so you have a fairly high metabolism. I doubt that the birth controls are having any significant effect, unless you are having nausea that's reducing your ability to eat. I wouldn't worry about this, unless your weight loss continues, and then see your doctor asap.