She has not felt the need to tell you to reduce your emails, even when you have given her an opening. She ought to be well trained in communicating about problems if she feels that there is one. So I would just assume that the emails are okay unless and until she tells you otherwise.

I like the ideas above about a) asking her to help you develop other coping mechanisms and b) setting your own boundaries around emails since you seem to be having some anxiety about the issue. Decide what you think is reasonable (once a day? once a week?) and try to stick to it.