Reply to Mic won't work with s4 anymore...

Hey guys just wondering if anyone can help me solve this issue? A few gigs ago i plugged my mic into my s4 and when i went to talk through it nothing came through. I turned my mic gain and mic volume all the way up. Nothing. I checked my input settings to see that nothing was connected, however when i go to click the drop down menu it only offers me channel c/d - left/right, for input options. And neither of these two work.... Not a big deal as i usually have an external mixer to plug my mic through but i like having the s4 act as a mic input for smaller gigs where all i have is the s4. Any help would be greatly appreciated!