Is my tarantula dead or is this normal.

Hi I'm a beginner tarantula owner and this is my first. Its a Mexican red rump (Tliltocatl vagans) and I got it 20 days ago. I got it from a pet store and the worker said he had just molted. As soon as i put him into the tank he goes into the hide and by the next morning its sealed off, I have not seen him since and I'm starting to freak out. I left a cricket that I'm pretty sure I killed (on accident lol) into the tank and the next morning it was gone so im assuming he possibly ate it or it was still alive and went elsewhere. Is this normal behavior or should I start to worry?