My i pod 3 gen home button isnt working what to do?

Well i used to have a 4gen but it broke so we used my brothers warrenty because we didnt have a warrenty for mine my brothers got lost/stolen but his was a third gen so as a result of using my brothers warrenty for 3 gen i got back a 3 gen i pod now i have no problem with that the thing is that in order to get out of an app i have to press the home button really hard and it annoys the hell out of me it was a lot more sensative the first week but than it got really hard to handle i mean the 4 gen was easy the home button was sensative but not to sensative just right and my brothers old 3 gem was like that too how can i fix this problem