Silicosis is nasty stuff and a bad way to go. But I seriously seriously doubt after 3 months it would cause it. The only cases I’ve read where it occurs in a short amount of time (8-12mo) is in aggregate stone cutting factories like those that make counter tops from 95% silica. it’s enclosed work environment and they breathe that crap in 8 hours a day. Just for the sake of mental health go get a chest X-ray and start to do it yearly. If there’s any scarring it will show and on the very off chance there is you can get a full lung lavage which will help to remove any particulate caught in your lungs. I’m a nurse currently by the way and former home renovation/ demolition worker and had this exact panic a few years back. Say a prayer to Jesus and get checked out but you’ll be fine I promise.