Keyboard Problems

Hi, so a couple months back, my 3 key broke on my Macbook Air 2013, though the key wasn't there, it was still functioning so I let it be, and I didn't go follow it up at an Apple Centre. A couple days back, the key stopped working and became unresponsive, and I was confused, and this was a worry as my password contained the number 3. I restarted my laptop a couple of times, and after a hour it worked which was great, but now it keeps spurting 3's everywhere and its annoying, I can't type properly or take notes at school. Does anyone know how to fix this?, or do I have to go to an apple store.

E.g. (He3llo this is 3wh3at3 3happe3n3s333 wh3en I st3a3r3t33 3typi3ng33 and its be3co3me 3qui3te3 a nuisanc3e3)

P.s This was hard for me to type up, sorry for any grammatical errors