Weight grill?

Okay sorry about the cringey request for information, but I would rather ask on here previously I go see a doctor.
I havn't have a period within at least 3 monthes.
AT LEAST.
The other Questions I've looked at on here said that sometimes when you don't weigh much your period stop... So...
I weigh 7st 1
I'm 5.4
I'm 13
I started on the 31st March 2007 (don't ask how I know that)
I'm naturally not highly big, but I eat anything I want. All of my relations are thin aswell.
So this couldn't be why it's stopped could it? This is completely majority.
It probably has zilch to do with bulk.
When you first get you're time it can be very unregular.
You can miss lots of period until you become regular.
It's most likely because you are youthful.
If you are only 13, this is totally middle-of-the-road. It can take your body year up to that time you become "regular" when it comes to periods. I've missed my time for about 5 months beforehand, and I'm 15. No worries!! :)