Shouldn't my metabolism be faster?

So I guess I'm at the maitainance forum now - I've lost 20 pounds and, though I was initially planning on losing more, have gotten several comments on how skinny I am lately. My mother, in fact, basically told me that if I lose any more weight I'm going to look like I'm anorexic. So here I am. My problem: I've been eating about 1400-1450 calories a day, and I seem to be maintaining my weight. As an active teenager (I do track and lift weights practically everyday after school), shouldn't I, in theory, be able to eat more and not gain? Honestly, I'm kind of worried about this. I'm scared tat I've damaged my metabolism. I'm actually going to up my calories today and see what happens: I plan to eat around 1500-1550. I'm 5'5", 130 pounds, 15, and pretty active, as well as fairly muscular. Can you help me figure what I should eat to maintain?

http://www.hpathy.com/healthtools/calories-ne ed.asp

Try that and see what it gives you, then adjust your calories to whatever makes you feel comfortable. If you do plan on increasing calories then increase them slowly every little while, that way your metabolism will adjust to it.

at your age, that's a super low calorie intake.  even if you played video games all day, i'd guess you should be able to maintain at 2000.  perhaps all the weight loss and low calories (how many were you eating when you were losing weight) has slowed your metabolism somewhat.  i do recommend trying to pick things up, gradually if at all possible.

when i was losing i ate around 1250 calories a day. i'm now eating 1500 calories and haven't gained any (i've stayed in the 127-130 range) and i'll probably up my calories again next week by another 100. the other concern i have is that i really don't get that hungry sometimes, but i eat because i know that i should. i don't know if i'll ever get to stop counting, because i would WAY undereat if i didn't count. if i ate when i was hungy and stopped when i was full, i'd probably end up taking in 1200-1300 calories a day. and i'm pretty much where i need to be weight-wise. *sigh* this prcoess is so complicated....

sometimes when you undereat for a long time, your appetite dies bec your metabolism dies.  starving children in africa lose their appetite altogether, and then when food's presented, it's often hard to get them to eat!  so reawaken your body by making sure to nourish yourself.  it's a process.  you'll get to the point where you feel hunger again, you feel energized by food, and you will need more than you're eating to get thru the day.  glad to hear you're staying on top of your calories, be when you undereat, you're not only shortchanging calories:  you're often not getting sufficient vitamins, minerals, fats to support hormones and bones, etc.  good luck.