Why isnt my iPod 4g not recognizing/ connecting to my wifi?

So the Saturday after Thanksgiving, I sent in my ipod to get its screen fixed since it was cracked but it worked fine even with the screen shattered. 2 days ago i have recieved my ipod back and when i turned it on it needed the wifi which i understand. But since i recieved my ipod, it hasnt been working properly wifi wise. It hasnt been recognizing my homes wifi or any type of wifi for that matter. It only pops up when my ipod is directly next to the router. My homes wifi is password protected. Before, it was able to instantly connect to the wifi and i was able to go wherever in the house and it works, now it doesnt. I cant pull my iPod back 5 inches without it disconnecting. The wifi only stays when its next to the router. Why is it doing this and how can i fix it to the way it was?