Whats going on? please help.?

I was supposed to start June 15 but I have been up to 2 weeks late before. But this time is different. I had some really light spotting on the 13 and 14 and then today i wiped and thought I barely seen some pink but I still haven't started. I have the paragard iud which has no hormones so u still get a period every month. I will b 2 weeks late this Wednesday but I'm kind of worried as what could b going on cause I have never had light spotting and then never start. I took a test at 1 week late and it was negative. I have had the iud for a yr. Should I take another test. Should I call the dr tomorrow or wait another week and c what happens? Thanks for all input.