How do i know if my 3mos old has RSV?

My 3mos old daughter started with a cough on tuesday nite and its rapidly getting worse she has a runny congested nose she seems warm at times but so far no fever shes restless and irraitable shes usually such an easy happy going baby but shes very fussy now i took her to her pediatrician today and there is wheezing in her chest they prescribed albuterol but didnt swab her for rsv they just said if she gets worse take her to the ER or to her DR ASAP but is this just a cold or the beginning of this ugly virus???