blessings dorkboy! haha
simply becoming conscious of your breath, feeling your nervousness, and just observing it without reacting to it is the easiest method… just allow it to be… all things must pass and this too shall pass… if you let it… try to make peace with it, not to fear it or resist it… if anything resist the urge to fix it… just observe and be aware of it… if you can hold a space of peace despite the reactions you are feeling it will dissolve of its own accord…
when you feel nervous, just feel it, don’t judge it… watch your breath… be calm… don’t judge it as right or wrong… good or bad… it will self-regulate if you don’t react… the body is very smart and it knows what to do if you let it…
that being said, it is not uncommon that people’s bodies can be conditioned and accustomed to things that are less than best… there are always upgrades to consider… and that anything is possible…
You might give a try to alternate nostril breathing… also known as nadi shodhana… abdominal breathing was mentioned here as well, that is also good, breathing by squeezing your belly in during exhale and pushing your belly out during inhale… this gives your lungs a complete breath, provides more oxygen to your body and brain and expels carbon dioxide…
there is a good book i recommend on my website (christianlocke.com) by Stig Severinsen called Breatheology - the art of conscious breathing. Stig is a champion freediver that can hold his breath for over 20 minutes and he has some great insight about breathing and yoga. There are also some free ebooks at (gutenberg.org) about breathing you can look up. I applaud you for taking initiative and desiring to help yourself by asking for the help of others.
I recommend you look deeply at what it is that makes you nervous, this short breathing is a symptom of that cause of nervousness and that nervousness is caused by something else in your core energetics… investigate it deeply and allow it to dissolve… try thinking of something that makes you nervous and feel where the sensation originates in your body, that is where your energy is blocked, just focus there, breathe into that point and send it love and light with your attention and ability to focus… just ‘really’ feel it and watch it dissolve… don’t view it as bad, just view it as it is… it will dissolve of its own accord and free that stuck energy which will then become available to you for the expansion of your consciousness. blessings…