Is it labor?

So this is my second baby and I thought I would know about if this is labor or not but have you experienced this? So about an hour and a half ago, I had some INTENSE back pain. Didn’t change if I changed positions or anything. Now.. they are mild and coming and going. But now what I feel is my stomach tightening very hard and I can FEEL baby moving down. With my son, I had this same tightening feeling but I felt like period type cramps at the same time. It feels like period cramps in my back!