If you had sex during those three missed days OR 7 days afterwards, you could be pregnant.
The one missed pill (either time) is probably nothing to worry about. Pills are not considered "late" until 6 hours after you were supposed to take them.
We cannot predict ovulation because you're not supposed to ovulate on the pills. It doesn't matter when you miss the pill, aside from the first active week - your chances of ovulation are no higher.
The fact that you don't have breakthrough bleeding could be a sign of pregnancy, but you also had a wacky cycle because of the three missed days previously.
You don't necessarily have to wait for a missed period. Most tests are accurate for most women 14 days (2 weeks) after unprotected sex. You could have gotten pregnant during the three days you missed the pill and seven days afterwards.
If I'm correct, you missed pills on the 23-25th, so seven days added to that is January 1st. Any act of unprotected sex during this time period could have gotten you pregnant. The 15th of January was when you could have started testing. A test will be accurate for you right now. Make sure to use urine when you first wake up in the morning.