13weeks pregnant very tired and sleepy at work right now! will one cup of coffee hurt?!-:/

No absolutely not: You can have up to 200 mg of caffeine in a day in pregnancy. And believe me, there have been a lot of studies that have come out in last few years on this. Most coffee 8oz is going to have around 100mg. A shot of espresso is even less at around 75mg. If it's your thing, i saw the other day that starbucks released it's pumpkin spiced latte early! :-).