You may want to check out "FirstVet" for advice on the current situation, and just for future reference. FirstVet offers "virtual" vet consultations via secure video link, and usually have availability within 15 to 30 minutes. I believe it is a 24/7 service. I am a HUGE fan of the service; I do not have any affiliation with them- just a great resource for pet parents.
It is not a replacement for your normal vet, but I've really loved it as an additional resource, especially to "sense check" whether a stressful, costly visit to the in-person-vet is needed and, if so, how urgently. They also offer advice on other interventions to help your pet with the particular concern, and help you understand what to look out for to know if/when escalation is needed.
You are able to provide a history of your pet, your concern, upload photos, etc. prior to your appointment to help use the consultation time efficiently. You get a written summary of recommendations, advice, etc following the appointment, and I think they can also send the summary to your in-person-vet if you want.
I have "free" access to FirstVet through my pet insurance, but I believe a consultation is reasonably priced if paying directly.
I spoke with a FirstVet vet this afternoon bc one of my cats (3 yrs) has been having issues similar to your cat. Things we are doing to help with hairballs/vomiting:
+Katalax,
+Royal Canin Hairball food, and
+daily grooming
(and ensuring all vaccinations, parasite treatments are up to date).
From the vet: Things you should look out for:
- Increased hairball frequency
- Overgrooming
- Vomiting fluid
- Lethargy