Having just come back from the Brac and had a new diver panic, I feel for the DM. I suspect the OP had a bit of panic and overreacted to a perceived problem. Low air isn't really life threatening. You should be able to get to the surface without an issue. In reality, the DM probably identified the low air issue and realized no problem. Keep practicing and when you look back in a few years you'll realize it wasn't a big deal.
It is taught in the open water course to plan a dive, discuss plan with buddy and execute plan. If problems arise, management of the problem is also taught. Practice, practice, practice.
It is taught in the open water course to plan a dive, discuss plan with buddy and execute plan. If problems arise, management of the problem is also taught. Practice, practice, practice.