Getting my period back

I am currently 15 years old and weigh 108 pounds at 5'7". I have not had my period since August 2008, and I am currently trying to gain some weight. 

I really want to get my period back because I DON'T want to become infertile because I DO want kids some day. I did go to the doctor and she told me I need to raise my BMI. I am finding this really hard because my weakness is my stomach. I get really self-conscious if I have a bump there and I restrict if anything goes there. I have gained a couple pounds, but I really need some help. 

How much weight do you think I need to gain before I get my period? Any ideas on how to gain? How many calories should I eat?

I also should add that I am a runner. I run 4 days a week for about 35 minutes because I am on the varsity field hockey team and it is required.

Thank you so much everyone! This is really a struggle for me and I need some support.

Yup, you'll definately need to raise your BMI. You haven't had yours in a while, so youll just have to be very very very very very patient . The longer you dont have it, the longer it may take to get it back.

Remember to get a good amount of fats in your diet. Not sure if you had an ED, because in that case there's a whole lot of psychological barriers to get past before you can simply accept that. Just remember - fats fats fats! Eat nuts, full fat milk, avocado, peanut butter, fish, and maybe even Luna/Lara/Clif bars.

Also, drink plenty of milk. Not sure why, but I read this helps. It also helped me to get mine back.

You'll also want to be as sediatary as possible. Is there anyway you can stop running? It is certainly not helping, if anything harming, your situation. It's hard to go from very active to nearly inactive, but it's neccisary unfortunately.

There are plenty of other tips others on this site will likely give you, but those helped me. I got my period at a BMI of about 17.3...it'll likely not stay at that BMI, unless youre naturally that thin, but you may need more. Typically, people need a BMI of about 19 to get and keep their period. I personally almost never had a BMI of 19, but youshould aim atleast there for the time being.

Good luck and take care xx