Help! Could it be time???

So since about 10:00 this morning I starting having contractions. Like strong enough to stop me in my tracks. They have been 3-5 mins apart all day!! I'm 31 weeks. Has anyone have this happen and it ended up being nothing? I really don't want to pack all my kids up to head in if it's not the real deal.

A little back story

I had my son at 34 weeks 4 days due to my water breaking but I had light in consist contractions since 22 weeks with him. And now this time I started having contractions at 22 weeks again. I did loose my mucus plug and there was a little bit of blood with it this last time I lost it. I do know it can regenerate itself so I'm not too sure. When my cervix was checked two months ago it was thick and long still.