It's a shame you have a problem with bees as they are pretty cool..we'd be worse off without them! Did you know that if a bee stings you, it dies? The sting is an integral part of it's anatomy and it leaves it behind fatally. Bees normally won't attack humans unless threatened - you must have seen pictures of people covered in bees unharmed....
I don't think holding your breath will make a lot of difference, frankly. If you try and ignore a bee it will nearly always just quietly carry on with it's business.
Wasps on the other hand are nasty little swines..... even I tend to run a mile when they start ganging up on me...! But even wasps won't attack unless they feel in danger.
I certainly think that if you move calmly away from the insect involved you have less chance of being stung than if you start waving sticks or your hands about.
I know it's difficult to be rational when you are panicking but if you can try and be cool with them it could make a difference to your enjoyment of your outdoor activities.