Not to rehash what I’m sure you’ve already read, but keep breathing out until you start sinking like a rock, and take smaller breaths in until you reach that 15’ mark. Or, tie an anchor to your leg. LOL. Just kidding, PLEASE, do not tie an anchor to your leg. The stress thing may cause it too. I recommend take a deep breath or two before you dump the air out of your BC to relax, and when you are ready, just start dumping the air and keep exhaling. Let us know how it works out.