My 2 1/2 yr old is doing the same thing, or has been, he is getting a little better. I think that it is just a phase for this age. The only other thing would be to consider if she is getting enough sleep and if there have been any changes in routine, new daycare, different work hours for you or your husband, change in diet, I would ask if there have been any changes in the daycare as far as their schedule goes, new children, new helpers, if this is a home daycare is the husband now laid off, and how much time is he spending with the kids, and in what capacity, etc. Did the clingyness start after a vacation, or family visit, or incident at the playground with other kids?
If all is normal and all the answers are no, then I would think that it is a phase, try to enjoy it because soon they won't want you in the room.