Back labour?

I'm 40+4 today and I've been having these intense backaches for the past 24 hours. They increase in intensity then fade out. Nothing in my belly, it's all in my back. I started timing them and this is how it's looking. Is this back labour? Should I head to the hospital since they're closer now?

Also lost my mucus plug through out the night and a huuuuuge chunk came out three hours ago