Droid for Verison, I cant hear people im talking to unless its on speaker?

I have a Droid from Verison, and I just got a call picked it up and couldnt hear anyone on the other line, but they could hear me loud and clear. But when i put it on speaker phone I could hear them good. Im wondering if a pushed a button or something but i want to be able to hear the person im talking to the regular way.|||the speaker could be faulty.. take it into a verizon store|||When you are in a call try pressing on the up and down arrows to adjust the call volume. the volume could be all the way down.|||go to verizon store or call them to see what is the problem