Hi dear Green Rain ~ I have to agree with Payne. I think that therapy would be the best answer here. There is a reason that you can't "break" these apron strings.

It undoubtedly goes back somewhere in your childhood, but it's imperative you find out, and where.
Therapy would help you identify why you have these issues and assist you in getting rid of them without hurting your mother. If she IS clingy, you will have to learn how to ease away from her without totally devastating her. That can be done, with help. Get in touch with your medical doctor as he will know the right therapist for you. I hope you'll make the call soon -- the sooner you can get into therapy, the better.
I wish you the very best! God bless and please keep visiting us! It helps to vent here, too! Hugs, Lee