You never really knew this person, u only knew the fantasy version that you created of them and now you can actually see them as who they are, now u get to see their true colors, because when we like someone, we tend to view them differently, we view them with fewer flaws and this is exactly why u can't catch feelings too fast when getting in a relationship, because if u do you will not catch the red flags. God has better things for you, so if you thought that this person was great, just wait.