My son was like this almost constantly until he was 11 months old (long complicated story which I will not bore you with now). The things I found that helped were:

Put a bowl of water under her cot at night, the moisture in the air as it evaporates will help her breathe

If you have any wet clothes, hang them on a clothes rack in her room, for the same reason

Put some eucalyptus oil on karvol/vicks on a cloth in his room with her

Raise the head end of her cot (I put a pillow under the mattress and this seems to be more comfortable than raising the feet of the cot)

Consider having her in your room so that you can hear his breathing and will be more assured of a better sleep yourself

Big hugs, it is a scary time when your child is ill but most recover from bronchiolitis fast. If you are in any doubt don't be concerned about taking her back to the GP.

T
xx