When to be concerned? 27wks5days- preterm labor symptoms?

I’m 27wks 5days and I have been having menstrual like pains and cramping off and on for the last few days. I am fairly active and I have been drinking as much water as I can. The mensural cramps are starting to become uncomfortable. They are not painful yet, but I’m not sure if I should be concerned. My husband does not think I should be concerned until they are super painful. I just am not sure what the symptoms are for preterm labor. I don’t want to waste an entire Sunday at the emergency room for them to tell me that everything is normal. This is my second pregnancy and this never happened with my first. My question is when should I be concerned with menstrual like cramping? I’d appreciate any advice.