So I've been working with this guy for about 6 months, we chat casually but not that much. I sent him a message the other day to ask if he wanted to go for a drink sometime and he said yes and put a 'x' at the end. I did ask as a friend but considering we don't actually know each other that well, is it possible that he thinks that I've asked him out? When we do meet, how will I know whether it's meant to be a date or just something casual?