Hi,
go to a sexual health clinic and get a swob done for thrush, cytolitic vaginosis and Bacterial vaginosis etc . Don't through thrush treatment or anything else at it until you know what it is. The antibiotics may have upset your microbiome. You probably need to get tested for UTI if you have symptoms also.
Wash without soap, or use hydromol ointment , use Yes VM on the outside to relieve itchiness.
Once everything is ruled in or out, consider using estrogen cream on the outside to strengthen the tissues and vagifem inside.
Consider refraining from sex perhaps until you get things a bit more under control. Maybe look up smart strains vaginal probiotics or there are other makes out there.
Pmx