Hello, I'm Approx. 2 Weeks Late, Had Brownish Spotting For

Hello, I'm approx. 2 weeks late, had brownish spotting for 2 days now there a mucusy discharge. mild like cramping which comes and goes and now my backs getting sore. Boobs didn't get tender with my last baby 8 yrs ago, and they not sore now. I had a miscarriage bout 2 yrs ago. I haven't don't preg test yet but with the back pain I'm getting a little concened... should I be worried? when should I test?