Why Won't The Sound Work On IPhone 4s

My sound was working one second and then the next, it stopped working. My volume adjuster disappeared every time I press them. I see the speaker icon is there, but the gauge bar is completely gone. I can only hear stuff when I plug in my headphones. I tried everything I can think of to get it to work like the toothbrush and blowing into the bottom of the phone trick, the Find My iPhone trick, and resetting my phone. Neither of these worked at all.