Too bad is a curious phrase. In North America, it can be used as an expression of sympathy, the equivalent of "I'm sorry".
In Britain, it is almost always used facetiously as if to say, "Well, that's your problem."
There are consequences to being misunderstood. I once had an Internet conversation with a friend in the UK who was suffering terribly from arthritis. Trying to be sympathetic, I said, "That's too bad." The poor chap got pretty angry at my apparent callousness.
Watch out how you use that curious phrase, and who you use it with, or it might be too bad for you.