How likely is false labor at 39 weeks?

So I’ve had false labor on and off since 31 weeks, I’ll get really strong contractions that will be about 5 minutes apart, think I’m in labor, and then after a few hours they just stop and disappear. I’ve been through it so many times already I’m not sure if I’m having real contractions now or not. This is my third baby but I’ve never had false labor with the other two, I just had strong contractions that woke me up and I knew. This time I have no idea what to think and I’ve been in denial. I had sex earlier this morning and I started to feel achy, took a shower and still had a back ache, and as the day has gone on they have gotten stronger but not quite strong enough to where I think it’s real. They have been between 5-4 minutes apart. How likely do you think it is I’m still having false labor at 39 weeks?