The fertilized egg attaches itself to the uterine wall a few days after conception to cause what is known as implantation bleeding
or spotting and starts to produce hCG. Once the egg is fertilized, it will travel to the uterus for implantation. During this time, it will continue to grow in size, its cells dividing and reproducing. The process of traveling and implantation generally occurs anywhere from 10 to 14 days after ovulation and fertilization. Some have reported having implantation bleeding as early as 6 days after conception. Spotting that occurs about a week after ovulation is likely implantation bleeding, which is typically very light pink or brown vaginal discharge and only lasts a day or two. Your bleeding seems a bit too early to be that of an implantation. Bleeding after a vaginal sex is obviously never normal. Bleeding after sex may have a numerous causes, ranging from abrasion from sexual intercourse to a naturally occurring virus known as HPV which causes cervical cancer. However, in most cases, it is the cause of a harmless, treatable cervical changes. That said, any abnormal bleeding must be looked at so it is important to have a visit with an OB/GYN soon to determine the exact cause of your bleeding. Good luck.