I was playing and it was very windy. On the first tee box, a huge gust blew right at the top of my swing. The ball blew off the tee on my downswing and rolled a couple inches in front of the tee. I couldn't stop the swing so clipped the top of the tee (which no longer had a ball on it) and then the bottom of the driver hit the ball that was still rolling forward. The ball skidded off of the tee box and into a creek.

My group gave me a free mulligan since it was a weird situation, but no one actually knew what the rules are.

Anyone know whether you get relief in that situation?

if it fell off during the swing and you made contact, it counts

Rule article

Should have went up and took a penalty. That counts.

Thanks guys. It was a casual round with no money (and the first tee where we hadn't even hit the range) so the free mulligan seemed right, but I know for next time what the rule is. Would have been pretty punitive to be hitting 3 from in front of the creek, but I guess that is the rule if you're not good enough to stop the downswing.