Welcome aboard, Cannabisdude.

Those are cotyledons and that's just what they are supposed to do.

They are the stored energy that is used to produce the first set of true leaves.
When they shrivel up, (and they will), it means that your seedling is now a young-ling and you can begin to give it nutrients.
Start with 1/4 strength or even less.
Different strains have different needs.
Fun, ain't it?

Aloha,
Weezard
.