Confused and could use guidance

So since 8:45 CST I've been getting strong period like cramps. They come and go consistently and my stomach gets rock hard. But they don't make me stop talking or lose my breath. They are definitely painful though. I've also gotten strong lower back pain now. Trying to stop and time these bad boys but my question is, how do you know when it's time to go to L&D? Am I going to be screaming in pain? Or is they too late? I have a very high pain tolerance. Any advice?!