Hello girls! My back has been hurting all day, I can't sit or bend ove...

Hello girls! My back has been hurting all day, I can't sit or bend over. Just now, for the past hour, it started hurting intensely like the spasms during my period, but it only hurt for a minute or two and then subsided. However, for the past hour, my abdomen has been feeling as hard as a rock and cramped up. It cramped up suddenly and didn't let up for about 30 minutes. Is this normal? Or should I call an ambulance? But there's no pulling pain in my lower abdomen, the pain is only in my back, intensifying like the spasms during my period. What should I do?