Hi,
Welcome to ehealthforum.
You are not protected while on your first pack of pills. If you had unprotected intercourse during the first month of pill use, then chances of pregnancy are high as shown by the first test that you did. A reconfirmation should have been done with blood HCG levels if pregnancy was suspected.
Your absent periods can still be due to pregnancy unless proved otherwise. Go ahead with a thorough evaluation, blood HCG level estimation and an ultrasound scan to confirm/rule out pregnancy, and to get started with further investigations to look for any other underlying causes (if not found to be pregnant).
Take care.