How high do your bs levels rise with a cold?

I apologise if this has been asked and answered before, I'm struggling to navigate this new forum set up! I'm wanting to know how much of an effect illness has on people's blood sugar levels? I recently stopped metformin (following Drs advice) due to 5 years of horrendous side effects. I am still taking Alogliptin. I'll be honest, due to financial restraints, I haven't been testing much over the months of lockdown so I don't have a comparison (dr won't prescribe test strips as type 2). My levels are very, very high this last week (morning around 16, dropping over day to around 9). I'm eating low-ish carb. I also have a cold, not bad but sniffling, sneezy, slightly sore throat, temp normal. How much impact does a cold have on your levels? Can it have a 8-10 mmol increase on bs levels? I guess stress levels are higher too. I'd really appreciate people's experiences and opinions. Thanks for reading.