Mic Failed on My 5s -- I Think It's Trying to Send Me a Message

I kid you not. Shortly after midnight, the mic on my 5s is no longer working (which is odd since there are three mics but I'm going to speculate that if one fails, they all cease to work). Siri won't pick up on noise and none of my sound recording apps will record sound (the resulting file is silent). It's not an issue with the speaker, which is odd since I've found very few reports of a mic failing on a 5s. I'll try a software update but has anybody had a similar issue?

I do need to test a phone call in the morning but I'm going to just assume that the other person won't be able to hear me.

Am planning to sell in November anyway when my update date comes but still don't feel like taking a trip to the Apple Store, especially if it becomes slammed for a launch.

It keeps momentarily working then not working again. Restarting the phone doesn't fix it, and in a voice recording it kept cutting out for minutes at a time. Will see if updating to iOS 8 fixes it.

This is odd since I've only found people having this issue when they got their 5S/5 or when they updated to iOS 7 so I'm not sure if it's a software issue.