Dear Alessandro.
I mostly agree with all what it has been said here.
First of all I would like to tell you that you are not Special. In the good meaning :-D You are just one more of many divers that struggle or panic when they have water in the nose. I never studied numbers but i am pretty sure tat it is the skill that most of my students struggle.
So, relax. You are having a normal problem on the process to become a Diver. One of the aims of the confined training is precisely to learn to calm yourself down when things go wrong instead of just letting the panic dominate you and swim up. Some things that help to my students (i don´t say there are not others) are:
1.- Relax. When you feel the panic coming, take control of your mind. You know that the option of swimming up to the surface will be always there, so give it a try. Stand the feeling as much as you can before going up, try to concentrate on breathing slowly and you will see that after a little while the panic starts slowing down until it disappear. If it doesn' t, you always will have the option to go up. So talk to yourself and remember that is the brain playing tricks with you.
2.Cheat: There is certain actions that you can do that at the begging will help you to stay down and recover your calm:
-Pinch your nose: When you feel panicking, pinch your nose so the water will disappear from it and while pinching your nose you can relax yourself and get ready to release it again. If the panick comes back, pinch your nose again.
-Exhale through your nose. While exhaling through your nose the water cannot go inside the nose. So i have students that in the beginning every time they have no mask they are exhaling though the nose// Pinching the nose when breathing in.
Those are little things you can do to start the path to master this skill. At the end you will have to be able to remain calm and comfortable without mask, but as said, at the end, sometimes this is a long path, sometimes it isn't.
So I hope this helps you. I wish you luck. Remember: Everything is in your head and you are not going to drawn because some water comes into your nose. So don't let your panick control you.
Happy bubbles
Gery
Diving tip of the week:
Scuba Diving Tips: The Bad Habit of Overweighting