Doing something is definitely better than nothing if that's where you were before you started walking on the treadmill! And I think your idea of how to make things increasingly more challenging by upping the speed & incline is great. Running is not for everyone and really, the best exercise is the kind that you don't dread doing. So if running is less appealing than death, I'd stick with walking! Great on the no sweets and w/the vegetarianism, just be careful not to overindulge on too much fruit (I've been told too much fruit can have an effect of inhibiting weight loss and that 2 servings is a good # to hover around) or too much of the bad carbs, processed stuff, etc.
Yes that is really good and you can make it better by adding a little more time or adding the speed of the treadmill but however you are doing great. Goodluck!