What Causes Numbness In The Right Leg And Back Pain After Using Ipills?

I have been on a birth control pill for 1 month a a week ago my right leg went numb on the top part from just above the knee to a few inches below the hip. No pain at all. My lower back hurts so I may have a nerve problem. Do you think my numbness could be caused from a blood clot? I am 44 years old.