turns out the "4" key was stuck even though it didn't look stuck at all. the funny part is that apparently this brand has a recurring issue with the number 4. the only reason I realized what was happening was that I was reading reviews of keyboards I could potentially (not) buy and one of them was from this brand and someone who wrote a 1 star review complained that the 4 key got stuck. I pressed it on my keyboard and suddenly everything was back to normal again. Well not everything, the built in scroll wheel has been broken for several months lol