When performing oral sex on the other person it is all about "their thing". Listen to what she is saying as the more she is turned on the more you will be too!
Sex clearly takes care and tact. If someone is doing something (the man or the woman) that is not comfortable or exciting to the other, they should try to learn from what the other one says. When you say she constantly directs you instead of "letting me do my thing," it could be that your "thing" (which possibly has worked for other women in the past) simply doesn't do much for her. It's not a one-way street, it's more like a dance.
Your description could be of a shrew telling someone what to do all the time (and if it is an extension of how she is in other times and situations, she might be no different in bed) or it could just as easily be a description of a guy who has an idea of how to do something that isn't going to work who just keeps doing it, and the woman trying to get him to do something more stimulating. Oral sex done badly is not particularly fun.
So I guess you have to decide together what it is about your oral technique that doesn't turn her on, and whether it makes you feel insecure to hear her say that it isn't turning her on, and what you want to do about it if the way she reacted made you feel stressed.