Microphone and sound issue + Mac + Discord

Hello Guys. This is my first time here and I really need some help. I'd be really thankful if someone could give me a hand. I downloaded Discord, I tried for few times and adjust the volume and some different functions. One day, the sound was too loud I shut Discord immediately.... The next thing I found is I can't hear or speak on both Discord and League of Legends anymore... I re-downloaded both and re-set up everything... its all in vain... I also tried with and without headphone. The weird thing is I can still facetime and video chat... Just both Discord and LOL are no responding at all. It's a Mac book pro Please help me.

Thank you.