Unsure!

So for the past 4 days I've had really bad back pain, today it eased up abit but suddenly this evening its come back as a really low dull aching, I've got period type cramps too and I have noticed the last couple of days my discharge has really increased!!!

I'm worried incase it could be preterm labour starting, I'm 30 weeks this Friday, although I've no history or preterm labour before.

I tried to call my midwife but no answer and I don't want to both the delivery suite, especially with the covid 19 about.