Help with my coolant leak!

I’ve been having a slow leak that hasn’t really given me any issues until last Friday when I topped off my coolant before heading on an 8 hour drive and it started to smoke when we were at the fast station. It was spewing coolant from this spot but I can’t find exactly where from. I have still been driving it because it doesn’t leak as bad when I have a full tank of coolant. I don’t know what I need to replace so I need help! Thank you.