I'm not an HR expert, but perhaps it would help if you drew up a set of possible interview questions and asked a trusted friend or your DH to do a mock interview(s) with you. Perhaps that would help loosen you up a bit and get you used to being both candid and persuasive in talking about yourself.
Good luck!
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher