V.W.
I would go ahead and call your doctor and see if they will see you early. I'm assuming that your appt tomorrow is just a regularly scheduled visit, right?
During pregnancy, your risk of DVT (blood clots in the legs) is increased. Not trying to scare you, but that is a risk during pregnancy. And if you are having pain in your leg that you can't explain, then you need to see your doctor. Call them and ask about the leg pain specifically TODAY.