Primolut N (norethisterone) is commonly used to delay periods for short trips, and it's generally safe for healthy women to use this way for a few days. Your trip starts tomorrow, so timing matters more than the medicine itself here.
Next Steps
Please see your gynaecologist today, even online if an in-person visit isn't possible tonight. They can set the right start day based on your irregular cycle, since starting even a day late can mean it doesn't delay things in time.
Health Tips
Don't start this on your own. In some women it raises the risk of a blood clot, which is why your gynaecologist should confirm it suits you first.