I have a sinus infection after a 3 hour flight. I feel horrible, I'm hot then cold, I'm on amoxicillian, & my sugars are from 89 to 400(after breakfast). This is day 8. Does my doctor need to know about this or is this normal when the body fights in an infection, Thanks. I should walk & get that 400 down but I really want to sleep. p.s when my dad was on insulin he'd adjust the insulin to get his number slower, does metformin work in a similar way?