I had intercourse a day after my period ended. i usually have a cycle of 26 to 28 days. could i be pregnant. and can a pregnancy test be accurate 10 days after intercourse?

If your period lasts for 5-6 days, intercourse on "day after period ends" should avoid ovulation days, but a pregnancy test "10 days after intercourse" is going to be negative even if pregnancy has occurred. Wait another 7-10 days, and if your next period has not occurred, obtain a serum HCG test, which is very accurate for pregnancy detection.