Back spasms = contractions?

V • After 14 months of struggle, had baby girl in 10/2015! So blessed...
I'm 36 weeks tomorrow. I've been having sharp stabbing pains in my left lower back every 10 minutes that last only for 20-30 seconds for the last 2-3 hours. I've been drinking water and changing positions. It never wraps around to my abdomen. Any chance these are contractions?