Computer select glitch

Hi guys! I was loading up my Mac for like the 4th time today but this time there was a glitch. Whenever I select a file, it auto selects it and won’t deselect even when I press another file (kind of like I’m selecting multiple files). Also, whenever I try to open an application, it sends me to the applications folder instead of opening the app. It’s really annoying! Does anyone know how to fix this?!? Thanks!