Back pain

I don't no if it's pregnancy related or my back causing the issue. Lower right hand side of my back is in agony- has been for two weeks. And it sends pains down my right leg, when moving quickly or walking especially if fast walking my back is agony. I am only 12 weeks pregnant aswell?! Never had this with my first. Not at midwife for another month, but might mention at my consultant appt Wednesday as it really is getting worse. Any ladies had anything similar?