PLEASE HELP

I am 18 weeks pregnant and have just woke up to a contraction like feeling in my back.. I've had a misscarriage before and it's the exact same stabbing feeling in my back only there is no blood?? Could I be having a misscarriage without bleeding yet I'm seriously worried? It's too late to ring docs and I don't wanna ring hospital if it's nothing it lasted about 5 mins and went away 😢