Hallow Dear, I do empathize your situation and feelings. However I would like to assure you in this situation. Though he withdrew his penis from your vagina before ejaculation, the possibility of deposition of pre-ejaculatory secretions (Precum) does exist. Precum does contain some sperms in it which are capable of fertilizing an ovum. So you have to consider the risk of pregnancy. However, you have taken Plan B pills within 72 hours of the unprotected sex. These pills are quite effective in avoiding pregnancy if taken within 72 hours of the unprotected sex, which you have done. There are couple of after effects of these pills. They cause some spotting to scanty bleeding few days after their consumption. It is normal, it is not menstrual bleeding and it does not need any attention. The bleeding you had on Tuesday or Thursday was this bleeding. Secondly, the following period after the pills may get delayed by few days to a week. However, you had your period a week after the initial bleeding. So you are not pregnant. The pills contain progestational medicine which can cause increased acidity in the stomach and gastrointestinal upsets by slowing the intestinal movements. Nausea you are suffering from may be attributed to the effect of these pills, which should be over in a week s time or so. Nausea does give unwell feeling, dizziness and tiredness. You may take some antacid like Pantoprazole for minimizing nausea due to gastritis. As you have suspected, it could be stomach viral infection also. Please report to your Physician for appropriate diagnosis. I feel you can safely put aside the possibility of pregnancy aside. Still if you want to conform you may take urine pregnancy test or Beta hCG test. I hope this helps you. Dr. Nishikant Shrotri