If it really bothers you, a call to your Dr in the morning won't hurt....but it is probably just the baby sitting on a nerve or something. Try and see if changing positions helps, like laying down on your side or go on your hands and knees. If so it's probably the baby. Otherwise, it may be a pinched nerve...
My doctor told me that if i get numbness in my legs or arms i need to come and see him. Not sure what it mean but if he mentioned it it must be something.