Mucus plug or bloody show?

So I'm 37.5wks and was having 5 mins apart contractions last night..ended up going to L&D, they hooked me up and checked my cervix which was 3cm and let me go.. as of now I'm not having any pain/contractions but I am having alot of discharge which I cant tell is bloody show or mucus plug...its my 3rd baby but I havnt experienced anything like this before do in hoping baby will come soon..