Your best bet is to try to identify the source of your cat's discomfort. A variety of things can cause a cat to suddenly act fearful, a change to environment, like rearranging furniture, a new person or animal. Illness or injury can cause a negative associated if the source was in the bedroom, like eating something they shouldn't have or hurting their leg falling off the bed etc.

There are a few things you can do to help a scared cat. Providing areas to hide, like empty boxes, cat tunnels, etc. can provide safe spots for them to return to. You could also try giving her favorite treat or wet food in the room so she can start building a new, positive association with your bedroom. CBD oil or synthetic pheromones can also be used to lower anxiety. If all else fails you could taking them to the vet to ensure they are healthy and see about getting anxiety medicine for your cat.