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If you have been regular and strict with the pill use, you need not worry about the pregnancy. If you are not sure of the pill use and have missed your pills in between, then there are chances of pregnancy occurring. Even pre-cum is known to contain sperms. But since you are at the start of the next pack, chances of pregnancy resulting is nil (if you have not missed pills in between).
Wait for your periods to start, if they do not start or if you have an abnormal period, get a blood beta HCG test done to confirm/rule out pregnancy. Stop using the pills if you suspect to be pregnant as it will harm the baby.
Report to your gynecologist for an examination and early confirmation of pregnancy.
Take care.