Enjoy the chocolate as long as your baby doesn't seem to be spitting up or having more gas than normal.
Alcohol and caffeine (like chocolate and coffee) are okay in moderation (this means eating 12 chocolate bars is probably not okay, but 2 or 3 is probably okay). The same applies to coffee (not the whole thermos, but 2 or 3 cups is okay) and alcohol (1 to 2 glasses of wine with dinner three times a week is okay as well). Here is more info from My Mamma's Milk (http://www.mymammasmilk.com/NursingTips.html):
Q: What is the recommendation about drinking and breastfeeding? I am getting conflicting information . . .
A: Alcohol in MODERATION is usually safe, though it is believed that the consumption of beer can cause an increase in milk odor, which may bother the infant. If you have a small amount of alcohol (one glass of wine) 3 days a week, there is no issue with breastfeeding. If you drink more that 2 drinks A DAY, you should wait 2 to 3 hours before nursing. Excessive drinking and significant infant problems (psychomotor delays) have been reported and studied. Best bet? If you really want ONE glass of wine with dinner once in a while, feel free to enjoy. This information is found in the Thomas Hale, M.D's book Medications and Mother's Milk 13th Ed.
:)