my new little rat not eating

Question
Hi I'm Jessica
I've recently purchased a rat 2 days ago and it's not eating or drinking I'm worried about him cause he seems like he's weak and not moving around as much as when i got him and I'm afraid he might die at this rate
today i tried to give him some food and put it to his mouth all he did was nip it not eat and then i gave him a little piece of cheese he took a bite and spit it out I don't know if he's sick or what any ideas of what could be wrong with him?

Answer
Where did you get him, if it is a petshop then I'm not surprised,  you should always go to a breeder for rats.  I presume you got two rats as everyone knows they must be kept in pairs.  How is the other rat, and if there aren't two, the one you have is probably depressed. What are you feeding them, what do you use for litter,  what kind of cage are they in?