Ouch!!!

I'll be 35 weeks Monday- my first baby I was induced and went a week over so I don't really know how it feels to go into labor your myself. But today a few times I had really painful what felt like back spasm in my lower back- only like 5 different times then they havnt happened since this morning. They pretty much took my breath away and were radiating- has this happened to anyone? Is this a sign of labor??? Any advice would be great!