Girls, I'm already 38 weeks pregnant, second delivery. So, about an ho…

Girls, I'm already 38 weeks pregnant, second delivery. So, about an hour ago, my lower back started hurting like during periods, but dull now, it's radiating down to my legs, but without pauses, previously there were no premonitions ? I haven't experienced anything like this before, and my first contractions if I'm honest, I don't remember)) Is this the beginning of contractions?