You sound utterly terrified when your fiancee is out of your sight. You said yourself that you don't know what you would do without him, and this is precisely the issue.
You are living every minute as though he were on the verge of leaving you!
This terror of being left explains your need to page him, have him call often, etc. The problem that you are experiencing is the result of emotional injury during the separation-individuation phase of early childhood. During this phase, every child needs to venture forth into the world, knowing that mommy will be there for emotional refueling, as needed.
Problems develop when mommy isn't available to offer comfort when the child returns to her. This leaves the child feeling afraid to separate from mom, for fear that she won't be there when he or she returns. This fear of separating from the love object carries into adulthood.
See my Advice Archives under separation-individuation and abandonment fears for more on this subject.
Your only real hope to heal this problem is to begin therapy now. You will need to find out who threatened you with abandonment or actually did abandon you.
Unless you identify the origin of your fears and work the issue out, you will continually live in fear. And, yes, your clingy behavior may drive your boyfriend away. So, make an appointment today. If you need help finding a therapist who knows how to work with this type of problem, let me know.