I'm scared I have cancer, my dr app not till monday?

I went to the Dr last week because of leg pain. My leg got unbearably itchy, at first I thought I had a rash but all there was was a few small red bumps. It started to feel like I had a huge bruise on my thigh but it wasn't really discoloured. The pain got so intense I could barely walk. My Dr said I should get a mole that is in the same area removed. The mole used to be perfectly round but this past summer it scabbed over and now has dark spots in it and the boarder fades into my skin instead of having defined edges. I have and appointment with another doctor on monday to have it removed but I'm really scared and it's all I can think about. Does this sound bad? what else could it be?