What Are The Causes Of Late Periods, Spotting And Negative Pregnancy Tests?

I have a copper iud. My period is usually regular 28/29 days My period this month is 16 days late presently. Large amount of negative home pregnancy test. Today had minor spotting, but also what I can only describe as waters breaking, lost a moderate amount of clear odourless fluid from vagina - didn t feel it happening just realised I was wet. Now leaking pink stained fluid. Any advice?