A. You may need a new set of dentures making. They can be made to fill out your face- and will be better fitting around the gums. As you use alot of poligrip, it may be worth thinking about having mini-implants placing into your jaw. This is a really straight forward procedure, and the implants will help to keep the denture in to stop it feeling so loose.
I would advise that you see your dentist about this- or alternatively, I would be more than happy to see you myself for a free consultation at my kissdental practice.