Is this labour?

[Spockrates]

I’ve started to have lower back pain that feels similar to the back pain I would get when I was on my period but I have had no contractions or tightening in my stomach I am 39 weeks

It's a cliche... but you'll know when it's labour.

I had pains every single night in the week leading up to my actual labour.

When it finally happened I'd woken from a nap with bad pains, ran a bath the general advice is if you get a bath and the pain goes away it's probably not labour but if it continues and gets worse it's labour.

It could well be. That's how my first labour started. Contractions came about 12 hours later, and baby a few hours after that.