Steroid meds always muck up my blood glucose levels, too. Thankfully only temporarily, and the steroids do make the symptoms of allergy (breathing difficulty and rashes) better very quickly.
When I was on Metformin, and only eating two meals a day, I took the tablets with those meals as the advice was to take them with food.
Unfortunately, we can’t really advise individuals on dosage or timing of meds , especially if there has already been specific advice from a HCP. Maybe ask pharmacist who prepared the prescription? I always find them very knowledgeable and they have best understanding of various meds and how best to take them when more than one med is involved.
Hope you feel better soon.