Maybe it's a bit of anxiety? I have panic disorder and I tend to get different feelings. Some go as far as to make me physically sick. I don't know if that's what it is for you but here are some things I do that you may find helpful.
Things that work for me:
Acknowledge your feelings as valid and part of your process.
Find some coping mechanism: your favorite record, an item you can touch and look at to distract you and comfort you.
Talk about it with people around you. Or don't talk about. Sometimes when I get weird feelings I remove myself from where ever I'm at and go sit down somewhere and chill out and think happy thoughts.
Envision yourself completing what ever you think may be making you nervous. Imagine yourself in the situation and having a good time. Make it real in your head!
Be conscious of what your eating. Avoid things with high sugar and salt (aka processed food).
Get lots of sleep. This can not be overstated! Sleep lots.