pregnancy test help

I need help. I just got a pregnancy test
1) it says I should wait at least 19 days after I think I got pregnant but it's only been 17. Should I wait? 
2) it says I should take the test 4 days before my expected period but my period is 4 days late. Should I still take it? 
3) it says I should wait until morning urnine. Do I have to wait until the morning I'll most likely forget?
Sorry I'm just really nervous my period has never been 4 days late