My rat is acting very strange

Question
I've always loved rats so my friend got me one for my birthday and he was fine but now he acts strange.He wont look at me without jumping and he freaks out when i try to pet him.Now he is building a wall type thing in his cage, like he does not want me to look at him.I have 2 cats but they do not bother him.what do i do to help me help him?

Answer
 How long was he fine before he started acting strange?  It sounds like he is not a well-socialized rat and doesn't like to be handled, unfortunately.  The only thing you can do is try to socialize him and hope he comes around.  Start by giving him treats and work your way up to petting him, then holding him.  It will take a long time and be a lot of work to get him to be somewhat normal, but with time and gentle handling he should eventually get used to you.  I hope everything turns out, good luck!