Oh dear Daisy
Are you saying you started your Empagliflozin and antibiotics for a urinary infection at the same time, or did you start on the Empagiflozin, then develop the UTI?
The way Empagliflozin works is to make you wee out the excess sugars in your system. For that reason, there is sometimes confusion because the urine tests positive for glucose. The downside is it can mean, for some people, they are more at risk of UTIs. Of course that doesn't happen to everyone.
Does your GP have a telephone consultation option available? It's very far from ideal when you have tummy pains, so he's likely to want to examine you, but it might be a faster way to talk to a doctor?
If you can't see a Doctor, then in your shoes, I would call in and ask for a consultation with my pharmacist. They are incredibly knowledgeable - especially on how drugs work and any interactions or side effects, so even if he can't maybe totally solve your problem, he might be better placed to guide you than seeing nobody for a while.