How to tell contractions?

Hello, I'm a 2nd time mom with a bit of concern. I'm 38 weeks pregnant and 10 days away from my due date. How do I tell what contractions are?

My first I never felt them once, had my checkup the day before she was due and got told I was in labor and that they'd induce me that night. Didn't even feel them when they asked me if I wanted an epidural halfway through my time in the bed before she was born.

This one, though, is different. General aches and pains from being upright/active, showed earlier than the first, an sits further forwards.

I've tried googling it, but Google doesn't really describe it in a way my experiences let me understand. It says they feel like period contractions, which I either never got or they felt like I was absolutely going to die, which this stage shouldn't feel like. I don't hold my stomach enough to feel if it's more solid or not, and I have back pain from doing physical activities like walking, bowling with the lightest ball I could (5-6 lbs max), and honestly mostly from laying in bed wrong thanks to not being able to get comfortable.

Is anyone able to describe their experience better so that I can tell when I go into labor, just in case it's early and I miss the signs? I'm a paranoid person as is, and I'd rather be sure of when it is happening so I can be prepared and have everything ready instead of a rush to the hospital.