An early positive pregnancy test becomes positive only after the fertilized egg has first implanted into the uterus and then sent enough amounts of hCG, human chorionic gonadotropin, the pregnancy hormone, into your blood stream and from there into the urine.
Implantation, when the fertilized egg implants into the endometrium, happens about a week after ovulation (range: 6-12 days), and it takes another 3-4 days after implantation (9-16 dpo: days after ovulation) for the blood pregnancy test to first become positive, followed 2-3 days later by the early positive pregnancy urine test, the home pregnancy test (HPT).
So, five days after intercourse is a little too early to tell, even with a blood test.
If you don't get you period is a week or so, try another pregnancy test, or contact your GYN. Good luck.