How can I manage my emotions during pregnancy?

Exercise and other. A walk can really help with emotions in pregnancy. For a lot of women, including me, emotions are more volatile, and this is normal. Crying at silly commercials is completely normal. Consider: yoga class, meditation, acupuncture, massage. Join a women's group where you can talk with other women about their experiences in pregnancy, or a book club, knitting, or sewing club. Good luck!
Carefully. Emotions can certainly run high during pregnancy. Hopefully with a loving partner and good family/friends, you will be able to relax and "handle the stress." however, if severe issues with stress/anxiety, than discuss with your dr. As psychiatrists are trained in dealing with this, even in pregnant women. Good luck to you.
Calcium is mood food. Calcium, 500-600 mg in the morning and the same dose in the evening might be a mood stabilizer. You need to divide it up and not take it all at once. Any calcium is fine, though you will see debates on which is 'best.' I think that if it fits your taste test, your convenience test and your finance test then it has past the test for you!