You can have up to 300mgs of caffeine per day. I think the amount in an espresso coffee is about 150mg and instant is about 80mgs where as a cup of hot chocolate is only 10mgs. Ive known people to eat a block of chocolate at a time while pregnant and their babies turned out fine. I think the main stress is more during the first trimester as caffeine can be linked to miscarriage. I think youd be fine with what youre having.