Is coffee ok??

I'm 5 weeks & 2 days pregnant. I have had great nights where I sleep amazingly and not so great nights. I think I must have a lot on my mind... excited about my first pregnancy, our house has been on the market for months and now we're feeling the pressure to move and I have a big job interview coming up. I'm curious if it's safe to have a small cup of coffee?? I'm hoping I'll be rested for my interview tomorrow but if not, I want to be at my best. Is coffee this early on ok??