How much do APs really matter?

I’m taking my AP chem exam in a few days and I’m worried about what will happen if I don’t get a 4 or 5. How much do colleges (especially Ivies!) care about AP exams in general? And in comparison to SAT II exams, extracurriculars and other parts of the application how much do they matter? If I get a 3 or lower, should I still submit my score? Or would colleges be suspicious of my not submitting my score?
Thanks guys!