Hi Karen
Welcome to the forum. Sorry you are having such a rotten time
If you were only diagnosed at Christmas time, you must still be in a bit of turmoil. There's a lot to learn and take in, but you have time. You are in this for the long-haul. And the more you can help yourself gradually get your levels back toward the 'normal' range the better you will feel.
As Northie says, it does sound like your levels are running quite high (thirst and blurred vision) I would guess you must be feeling pretty exhausted too.
The tablets you are on will help your body use the insulin you produce more effectively, but you can do an awful lot to help by taking a careful look at what you are eating.
Diabetes means that your body has a problem 'dealing with' carbohydrate. That means sweet things, like cake, biscuits, jam, honey, but also lots of other things too. Bread, pasta, rice, potatoes, cereals, oats, grains, fruit, even starchy veg like carrots and parsnips will all be broken down when you eat them and end up as 'glucose' in your bloodstream. Some (especially more refined or processed foods like white bread) will tend to get into your bloodstream faster, but one of the confusing things about the condition is that foods will affect different people differently. And even the same food can be OK for someone in the evening but cause a rapid rise in their blood glucose (BG) level at breakfast.
Take a read at the links on the page Northerner posted, and have a look around the other threads here and you'll find pretty much everyone talking about carbobydrate and BG meter readings.
If you want to help your Metformin work harder for you consider reducing the amount of carbohydrate you are eating at each meal. Get yourself a meter to test before you eat and then an hour or two hours after you've finished to see what the effect of the food was (you might get a meter/strips from your GP or you might need to buy your own). Don't get too horrified at the numbers to begin with (they are likely to be higher than the recommended range) but look at the effect of the food - how much it made your BG rise and how quickly. Then use that to change portion size and/or what's on your plate.
Good luck and keep us posted
🙂