At what point should I go to the hospital with contractions

So I’m 37 weeks exactly today. I started having tightening around 11am and random sharp pains. Nothing that was bad enough for me to think i was in labor though. Well over the hours they weren’t going away. Around 7pm I counted how many I had in an hour and i had 5 by 8pm. They are random not happening every so and so amount of time. Well I am having sharp left back pain when I walk. It is now midnight and still habing them randomly . When should I call on call? Or is this all normal?