My Dear Madam, The fact that you had your menses at the normal time after the unprotected sex during that cycle proves that you are not pregnant. It seems during that intercourse, you have contacted some sort of vaginal and/or sexually transmitted infection. From your description I guess, this is likely to be either Trichomonial and/or Yeast infestation of vagina. The former can be treated by metronidazole while antifungal pessaries will give you relief from the later infection. Gonorrhoea is another possibility which needs to be checked for. If present, suitable antibiotics will cure the disease. If ignored and delayed, may lead to infertility also by tubal blocks. Proper examination of the discharge is required before finalizing the diagnosis before starting any treatment. Please report to the Gynaecologist for proper internal clinical examination and subsequent treatment.