well, your foundation is settling and this sure is happening quickly.
Just a few questions:
I assume you on a slab foundation.
Do you have cable lok or some foundation system?
Was your home built during a dry season and now is it wet?
Are the cracks going in the same direction or is there a pattern of sorts? Is this a two story home? If so, do you have something heavy above this area? Like a pool table?
is your driveway, or garage, or any exposed foundation concrete area cracking also?
Notify the builder and have him/her see this and do not settle for a painter coming over and just caulking over this area. This is only a band aid approach. Keep an eye on this keep documentation notes, and people talked to and action done. This is awful early for this.