What's wrong with my tarantula! :(?

I have a chilean rosehair tarantula. I'm unsure of the and have no idea how old it is. the petstore had no clue. I named it rajah and have been referring to it as a he. Ive had rajah for a little over 2 months. I rarley hold him because I dont want to stress him out, but i feel ive been taking really good care of him, ive gotten extremely close to him. About 3 weeks ago i purchased a batch of crickets from a different petstore than i usually get his crickets from (the same place i got rajah is where i usually would get the crickets) i noticed that even though these crickets look the same they were a lot more energetic and they were also smart, everytime i would put one in rajahs tank it would do everything in its power to avoid rajah whether it would hide or hop around like crazy, or even escape out the tank! half of them ended up outside because they kept getting out and i didnt want to feed rajah a cricket thats been contamidated by germs and what not. anyway, rajah only ate 2 out of the 12 i purchased, and when i brought them home, he was due for a feeding. its been 3 weeks, and theres still 2 crickets left, and he will not eat them. i havent noticed any changes in his behavior, nor have i noticed any wounds. theres no dark spots on his abdomen, which i was told that would be a sign of a molt. other then him not eating he seems o.k but he ate really good every week when i first got him, actually he was a little pig, but now 3 weeks? im really worried, and the people at the petstores dont know squat. any ideas?