Am I underweight for my age and size?

I'm a 6'3, 15-year-old guy, and I weight 141lbs. The online bmi calculator says that I'm borderline, but that doesn't take into account that I run, bike, and play tennis a lot. My bathroom scale, however, says that my bmi is only 10. I've been getting several comments about being too skinny, and I can faintly see the outline of my ribs with my stomach relaxed. I've been getting tired, and periodically dizzy, but that might be because I don't get much sleep. My mom is underweight and anemic. I eat until I'm full, but how much I actually eat varys a lot.Am I underweight for my age and size?
im like 6'2 and 15, i think my weights about 150. some people just cant gain that much weight, but the dizzyness is a concern. maybe you work out and burn more calories than you eat.
Start taking a Multi-Vitamin tablet daily to provide your system with nutrients you may not be getting in your daily food intake.
You need to make sure you eat a good, balanced diet, including plenty of boiled or steamed vegetables. Drink lots of water, fruit juices %26amp; milk. Snack on plenty of RAW fruit %26amp; veggies.
NEVER skip breakfast. You get your energy for the day from your breakfast meal.
Try to get a good 8 hours sleep each nite. Avoid stress.Am I underweight for my age and size?
I agree with Moo Moo, you may just need to drink more water. Are you a small boned individual? Doesn't sound like you have anything to worry about, my friend.
Your weight is fine don't worry over it, and being 6ft 3 is also good. In my opinion. If this is bugging you why not see your GP/Doctor?Am I underweight for my age and size?
hmmm, well I wouldn't say your underweight, just a little slim. Drink more water :)