Is a complete course of 2 pills of postinor 2 strong enough? or do i need to take another dose?

Effective: If taken appropriately and early, like within 24 hours of having sex, it reduces the risk of pregnancy by up to 95%. A double course isn't necessary.

It is enough: Here are the instructions: Take 2 pills within 120 hours after unprotected sex. This 2-pill dose contains 1.5 mg of levonorgestrel. I am presuming you are using this for emergency contraception. 2 pills within 5 days of intercourse is the dosage for emergency contraception.