Caffeine free and insulin free

I stopped drinking decaffeinated drinks about 2 weeks ago. It wasn't intentional, I just ended up shopping when that was all that was on the shelf. After I suffered through a few days of nasty headaches, I decided that I wasn't going back to drinking caffeine on a regular basis. I've been drinking a lot more water; it's good for me, right?

When I started working out 3 months ago my insulin needs dropped dramatically. I went from taking 40+ units a day to taking 20 units day. Things remained stable until about a week ago, when my blood sugars started crashing in the early AM hours. I started lowering my insulin dose more and more until I was taking just a few units a day. Today when I saw the Dr. I asked if she wanted me to just go off the insulin or switch to oral meds for a few weeks. I got a prescription for Metformin and Saturday will be my first day totally insulin free. The doctor says that this med should boost my weight loss as well. That's fine with me. I've lost 16 pounds in the last 3 months according to the MD's scale. She's really happy with the 16 pounds but I'd really like to get this weight off faster.