Mon, you did read the book, right? Dr. A talked about this--he pointed out that caffeine hinders weight loss and, more importantly for us, it affects your insulin production as well. He suggests having no more than 2 servings of coffee a day. Green tea
does have caffeine, but it's
much less than in a cup of coffee, so you can have more than two cups/day.
I watch my intake and keep it within the levels that Dr. A recommends (at least on most days) and it hasn't been a problem. Stop kicking yourself and just look forward to losing more in the future, now that you know!