Metformin does take a little while to get into your system
@Maca44, I'm sure you'll be feeling better soon. Late evening meals aren't a problem for me...we eat about 8pm and it doesn't seem to affect my bloods, but I have to admit I don't know what Sitagliptin is like and hope someone with more knowledge can help.
Are you cutting down/out your carbs? I found once I'd been a few days with v few carbs I stopped feeling hungry and wobbly before meals. However, we are all different as you'll find on this forum. One thing is for sure, there's no such things as a "standard" diabetic. You may benefit from monitoring your blood glucose before a meal and again 2 hours after. As as type 2 you probably don't qualify for a free one on the NHS, but they are reasonably priced. I bought the SD Gluco Navii because the testing strips are relatively cheap.
As for being the highest reading your nurse has ever seen, there are lots of people here who were into 3 figures and have now cut that right back so don't panic!
Hope you feel ok working tomorrow.