My ridiculous metabolism

I don't understand why I don't gain eating 3000 calories a day for a week?  My stats:

Height: 5'3"
Weight: 118
Age: 20
Weight lifting: 5 days for 30-60 min alternating
Cardio: 6 days/week for about 30 min
Random walking: 1-1.5 hour total every day

What gives?  I mean, I like it, but I also don't like the fact that I'm still eating when my intake has already been over 2000 calories =.=

You don't gain because your body is using up 3000 calories.   Calories in = calories out.... no weight loss or gain.    I don't know why you think 2000 cals applies to you.    2000 calories is the amount of energy needed by the average 21 - 49 year-old, very lightly active, normal sized (120-170lbs) woman.  You're pretty young and you're extremely active.... both of which mean you need more to eat.   Why would you call that 'ridiculous'?....  Don't understand.

Enjoy this while it lasts.   As you get older and your lifestyle changes your energy needs will probably reduce. 

Wow!  That's kind of cool.  I guess I just associate 3000 calories with really fit guys I know who are constantly working out (more than me!) xD;  Oh well, I just wish sometimes I would enjoy my food more by eating slowlier instead of being just hungry and eating everything at once xD