I'm a little confused. You asked if the morning after pill would work after 10 days, but said she is 4 days late? If those 2 numbers are accurate, she would only have a 6 day Luteal Phase. I don't belive that is long enough to conceive. Or the numbers are off.
I get the feeling yr girlfriend is going to have her period and hopefully she's not pg and you both are going to be relieved from this anxiety..! But please allow me to give you this advice:get yrselves properly informed about sex,contraception and abortion.For guys it's just an accident,for girls it's really painful and can have consequences.I took me years and quite a lot of stress and pain to understand that i'm the only one who will protect me,never rely on the other person.But since you are a young puppy-saying that in a sweet way-you can make the difference,learn how to enjoy safe sex,you and yr gfnds will not regret it.Ughhh,maybe i sound like yr grandma but it's true!Good luck!