I think your first step might be not to think of it as down grading the amount you love her, or loving her "less". What she is asking for is for the relationship to function differently. That is changing actions not intensity of love.
Loving someone completely and fully including the parts that mean your relationship is going to be shaped differently then you feel like you want. Right now I say "feel like you want" because it doesn't sound like you've been able to give what she is asking for a fair shot just yet and that might take time.
Remember it's okay to ask her for help. Make sure you are clear and detailed about what she is asking for. I understand that what she is asking for might seem like "love me less" but really it is about the actions that you are taking that make her feel smothered. So try to find out how she would like you to act and just give it s shot. See how it feels. See if somethings work at lessening your stress, see what makes it worse. Pay close attention to your feelings and keep her informed about how it is working for you.