Caffeine During Pregnancy

Briley
I have read that the equivalent of a 12oz cup of coffee/day is okay, but that any more caffeine could over stimulate the placenta and cause a miscarriage. 
I really can't get by without caffeine (especially with this first-tri fatigue), but every morning while I have my small cup of coffee I get really nervous. 
Does anyone have experiences kicking caffiene? Did you still stick with the one cup rule? 
Signed an exhausted Momma-to-be 😩