Hi,
Metformin is the first-line drug for treating Type 2. That said, my BG was higher and I was put on Gliclazide initially, but last week the doctor put me on Metformin too. I am guessing that you are starting with one tablet with breakfast and will be increasing your dose over the next few weeks.
Metformin takes a while to work, but you should see effects soon if you have insulin resistance (Type 2). If you are Type 1 it may not have much effect in which case they will probably change your meds. There are separate blood tests that measure the amount of insulin your pancreas is producing and to detect an autoimmune response. Those will help them determine your type and, hence, treatment.
If you are not already doing so, try to get a glucose meter and test strips. Testing regularly can help you learn how your BG fluctuates in response to different foods and your meds.
I would hope your doctors are also planning to rule out other potential causes of your weight loss in the immediate future.
This weekend, I would suggest you lay off the drink. If you must, have a small amount of champers for the toasts. Also, lay off the dessert and try to limit your other carbohydrate intake (e.g. only eat a small amount of potato).
I hope this helps, it is a big learning curve initially but you will get there in the end.
Ellis