Hallow Dear, Improper use of condom can result in rupture of the condom which may cause pregnancy. Vomiting is one of the symptoms of pregnancy, if it is after missing a period. However, severe waist pain cannot be a symptom of normal pregnancy. If your pregnancy was detected by pregnancy test on urine, please get ultrasonography done. If the baby is found in the uterine cavity, no issue of concern; however, if the uterine cavity is empty in spite of positive pregnancy test, you should insist on investigations for ectopic pregnancy (pregnancy outside the uterine cavity). Ectopic pregnancy can cause such pain. Ectopic pregnancy does not grow and usually ruptures causing severe bleeding requiring emergency surgical intervention with many units of blood transfusion. However, if detected before rupture, it can be managed conservatively. Please report to your Gynaecologist ASAP. I hope you got the message. Dr. Nishikant Shrotri