My freezer isn't freezing anymore?

My freezer suddenly isn't functioning properly. Everything in the freezer is still cold but thawed out. In the refrigerator part everything is still cold. When I open the freezer I can hear something running still. The ice in the ice bucket was also melting and water was dripping from the shelves. I have no money at the moment to buy a new fridge or even get a repair guy out so i'd love to try some do it yourself fixes. Any help would be appreciated.