I have no clue what to think...

I have a Paraguard IUD, and ever since i got it 3 years ago my periods have been pretty on time with the occasional early period. I am hardly ever late and when i am i’m only 2-3 days late... every time i was late i tested just to be sure but always ended up being negative. I am currently 6 days late and threw up at work this morning. I got a bit of light cramps like right before my period should’ve started and a day or two after it should’ve started. Other than that i haven’t had any signs of my period starting soon. I don’t want to test because it’s always negative but i’m weirded out about it being longer than normal... what do you think i should do?