Please use this as a lesson learned. One set of flowers was not appropriate and three sets is way over the top pursuit.
I would not respond to her e-mail. You would not ponder so much if you sent a "regular" friend flowers for their b-day. She has thanked you for them and that is that. She also made it very clear for you not to do that again.
Unless it is something urgent (bills, finances) do not contact her again.
