Normal?

I'm 15 weeks pregnant and every time I walk around I get cramps in my legs and feet. Laying down makes it feel better but as soon as I start walking around it comes back. This is my second baby and I can't remember if I had it with my first at this point in the pregnancy. I have an appointment tomorrow so I will definitely be mentioning it to my doctor but I just wanted to know what other people think for now. Also, I have a very tilted uterus if that makes any difference.