waters leaking

Would like some advice please,

Hi I'm 29+2 weeks pregnant and have been told to expect baby girl to arrive early as I have had complications through out my pregnancy over the past 3 days I've been having on and off dull achy pain in my lower back and a heavy dull ache in my lower abdomen I though I was just Braxton hicks till this morning when I noticed that I was very damp down there I know its not urine and its nothing like any discharge ive had during my pregnancy just wondering how to tell if my waters are leaking?