Pregnancy can be detected by the routine urine test (the HCG test) anywhere between 7 - 17 days after the sexual intercourse. But it can be falsely negative if done early. So what you can do is ask your partner to wait for her next menstrual cycle. If her periods are missed consider getting a home urine pregnancy test done. Alternatively you can visit a doctor.
The chances for pregnancy in your case is less, but you can be never sure.
Even if she is pregnant she should not feel sick. Consult a doctor if the sickness persists