There is a hormone tablet gynaecologists prescribe to delay a period, but it only works if you start it a few days before your period is due, not after bleeding has already started. Going by your last period date, your next one may fall very close to the 16th, so timing is tight.
Next Steps
Please see a gynaecologist today so they can check your cycle length and prescribe the right tablet while there's still time before the 16th. Don't buy anything from a pharmacy on your own, since wrong timing makes it far less effective.
Health Tips
Once your period actually begins, it generally can't be postponed anymore, so earlier is better.