As you probably know, Metformin helps most diabetics control (lower) their sugar level. You don't say how soon after you ate that you checked your sugar level. There are 2 types of insulin; slow acting and fast acting. I believe Novolog is fast acting; whereas, the Metformin is a slow acting type of medicine.
To answer your question regarding Metformin, yes it will lower your sugar but it may not lower your sugar as fast as the Novolog. Since this sounds like a one time event, I would continue to take your Metformin as usual and check your blood glucose level more often until your insulin arrives - before every meal or snack. You want to see your blood glucose (sugar) levels going down to 70-140 mg/dl. If your insulin does arrive the next day (and maybe by the time you read this), you should be fine.
I wouldn't worry if your sugar level spikes this high, 326, so long as it heads back down within the next day. If your sugar levels stayed this high for 3 or 4 days or more, then I would see a doctor. But by then, you should have your insulin and be fine.
I know what you're going through because I am a diabetic, using 2 types of insulin for the past 3 years along with Metformin.