Hello!

I had my first sexual encounter on Dic. 30. Last period: Dec. 13 Cycle: 28 days.

Used protection: condom and birth control pills.

From yesterday morning I have been having cramps, like those I have when I am on my days. Is this normal? What could it be?

Cramps can happen for many different reasons. It isn't normal to have cramps after sex, unless your partner was very rough, or you have another condition that you weren't aware of before this (PMS, bladder infection, etc.)

We really can't tell you why you're having cramps. If this is a concern, see your doctor.