Hi Peadair - Frustrating that that infection hasn't gone. Whilst most of us would rather avoid the meds, sometimes we just need to bite to bullet to get rid of the thing.
Whilst your bloods are up a bit with the infection, the chances are the steroid will nt the numbers up again. To be honest, it seems like eating well, and by well, I'd suggest keeping the carbs tight, to limit the blood rises where you can, but also importantly test lots. I don't say that to frighten you or to rub your nose in the numbers, but to say if the numbers get very high; get yourself back to the Doc, call 111 or off to A&E for you.
I'm fortunate never to have taken oral steroids (have rubbed on a bit of steroid cream occasionally, but that doesn't count in this context), but I know when I go onto antibiotics, I quite often feel really, "Meh", whilst they do their stuff, but grind it out if you can. If, however, they upset your tummy, ask for an alternative.
I usually find myself eating lots of yoghurt when I'm on antibiotics, to protect my gut flora a bit, but that's just me.
I hope you're feeling better soon, Peadair, and a Happy New Year to you.