Help Me Decide!

I am 16, 5'2 and weigh 86 lbs. I've always been pretty thin. I get a blood test done every month to make sure i'm not deficient in anything (and I'm not) I've always been fascinated with weighing more. And not just normal weight, but something that stands out. Can anyone help me decide on what to do? I'm kinda embarrassed by this and don't know who to talk to and at the same time I don't want my family and friends to know. If I gain weight, I want to come up with a clever excuse so my friends and family don't think I'm crazy by doing it on purpose. PLEASE SOMEONE HELP ME. I've been stuck with this for a while...

Here are some pics.

http://sphotos-a.xx.fbcdn.net/hphotos-ash3/529687_532009073498606_1954718257_n.jpg

http://sphotos-b.xx.fbcdn.net/hphotos-prn1/66146_532009076831939_678077395_n.jpg

http://sphotos-b.xx.fbcdn.net/hphotos-ash4/427289_532009080165272_1695021138_n.jpg

(My collarbone)
http://sphotos-a.xx.fbcdn.net/hphotos-prn1/537998_532009126831934_65007013_n.jpg