Deep Sleeping Guinea Pig?

Well, my guinea pig, Popcorn, is really weird. She falls into a deep sleep right after she eats. Even if you poke her with your finger she will not wake up. But, I touch her rump gently and then she wakes up. It looks like she's dead and it worries me. She has only done this 2 times. Is this something I should worry about, or am I over reacting? Please Help! ASAP! :(