Coffee during TWW?

I'm not a big coffee drinker, but I do like go have a cup once or twice during the week in the morning. I don't drink mine black or with sugar, just with some milk (skim). I am in the tww process right now. I have no clue if there is a lil fertilized egg in there that has implanted or not.

But I was wondering do any of you other ttc ladies have a cup of coffee at all? Should I avoid having any like I have been? Or is it safe to have a small cup and it's not going to mess up anything that may (or may not) be going on in there lol.