4 daya after we had sex and she ia already having stomach aches and vomiting the sex is protected by the way. is this pregnancy or something else?

I doubt it is pregnancy unless it is from a previous encounter. When an egg is fertilized it take 4-5 days of travel till it implants.. You don"t usually experience nausea unless implanted and secreting HCG in the blood stream to some degree so its about 3-4 weeks post sex. If the next period is late would check pregnancy test.

It is something other than pregnancy. It takes about three weeks for the embryo to implant and make HCG that triggers the symptoms of pregnancy.