I think they can be linked - at least doctors think so - I remember a very odd conversation with my GP who was asking if my symptoms of thrush had gone and was the treatment effective, when the last time I had seen him was to get treatment for cystitis. I had a repeat when on holiday and found that drinking water did help and by the time I'd returned home it had gone, but you have my sympathies as I remember how painful it was. Can you make an early morning call and get an emergency appointment with your GP?