I Have A Diabetic Cat (new Condition). Her Blood Sugar

I have a diabetic cat (new condition). Her blood sugar went up to 734 when I checked her sugar at 8:25pm I gave her 3 1/2 units of insulin. Checked her sugar 50 minutes later and it had only gone down to 704. What should I do? My vet is closed now and tomorrow is a holiday? Thank you, Ann