1. If your period is 11th which was yesterday.

2. 14 days after the first day of the blood stain will be on 24h of this Nov month (2weeks after) counting from 11th.

3. 14th day is on the 24th February.

4. 3days before the 14th day is 21, 22, 23.

5. 2days after 24th February
  is 25th and 26th. 

6. 21th-26th February (6days) is when you are ovulating. 

That's  your fertile window and period.