25 weeks, 'back' contractions!?

Hey Glow Friends.. Since the start of today my back has been hurting. Then a few hours ago I noticed a pattern.. And I'm just a little scared. I kind of described to my boyfriend that it felt like back contractions and not to worry because contractions happen in the front (or so I thought)... It would be uncomfortable and then my back would get this pain that I had to breathe through. It wasn't excruciating but it was pretty painful! And for about 3 hours that's what it did, intense pain, breathe for about 20 seconds then it would go back to just being uncomfortable. It started radiating to my belly and I started freaking out because I'm only 25 weeks! Now it's eased off a bit but still get sharp on one side of me both back and stomach on and off and I was wondering if anyone has had these or experienced something like this? Any advice or reassurance would be really nice. Thank you