How long

How long after your period is late do you normally wait to test? I'm 3 days late now, normally not late at all, and too nervous to test. I said if it wasn't here by Monday I'd test, but now I'm not so sure I'll follow through. I could've sworn it was starting Friday. I thought I saw 2 of the tiniest little pink dots on toilet paper (not even dots... so small...) but now nothing. And of course I thought since it started when my doctor asked if I could be pregnant I said "no" So now I'm on medication that has a slight risk to cause birth defects. What do I do?