Hi, my last period date is 5th Nov. It is a 24-25 days cycle. I had an unprotected sex with my husband on 19thor 20th exactly did not remember. I do not want to get pregnant. Is there any possibility to pregnant ?

Whenever you have sex there is a possibility of pregnancy. Unprotected sex only increases that possibility.

Unfortunately you now have to wait to see if your next period comes. If it does not, take a HPT using first morning urine.