You're doing GREAT!!!!! Hey, walking away is better than blowing up! You can apologize for saying nothing, but you can't take back words you didn't mean. Just explain to her how hard quitting is, it can also be a tool for you to use to discourage her from smoking when she sees how her normally awesome and soft-spoken mom is reacting to her addiction. I don't know how old your daughter is, but if she's upset by a C she's obviously smart enough to know that quitting smoking is hard, and just imagine how much she'll admire the strength it's taking you to quit. Don't let her or yourself down, it's been 100 days, you can keep it up!