ANSWER:

If you saw your purity and performed ghusul accordingly, there is nothing on you. But if you didn’t see your purity and performed ghusul hastily, you are sinful and must give expiation. 

My query is that usually my periods last 5 days. This time, on the fifth day of my cycle, i performed ghusl and thought i was clean. The same day we had intercourse and there was blood,pure red blood which continued until the next day which made the period 6 days. What should i do in this case ? Do we need to pay any expiation or give charity ?