IF she had her period last week-ish. She is likely not pregant. As morning sickness usually dont show up for a month or two after the embryo was fertilized.
If she was on her period last week, the week before the period is actually the safest time to have sex. It is actually the safest time to have un-protected sex, as she has something like a 50% lower chance to ovulate, while the cemen is squirming around.
Basically it's too early. If she had her period, AND this is morning sickness, she has been pregant for over a month, wich would mean that this was likely a miscarriage or something along those lines. As it's not totally abnormal to have a period after she may become pregant. However usually morning sickness would take a while longer to show up.
As my wife just said. Have her pee on a stick. (pregancy test)
I highly reccomend wait about 2 weeks, and then do the pregancy test. And make sure she dont drink, smoke, or do drugs, untill your positive she's not pregant.
And if it's a boy, name it Kwaad. XD