Chance of pregnancy is very low, but not zero.
Since your periods ended on 8th December and intercourse happened on 19th December, this was likely before your fertile (ovulation) period in a usual cycle.
You also took i-pill on the same evening, which significantly reduces the chance of pregnancy when taken within 24 hours.
Next Steps
Wait for your next period (it may come early or be delayed due to i-pill)
If periods are delayed by 7 days, do a urine
pregnancy test