How much do you bleed when your hymen is broken?

It can vary from woman to woman. It is quite a shock to the system when a young woman loses her virginity (physical shock) so this could have also brought on an early period. It isn't anything serious and you'll just be fine.

Some women don't bleed at all, some just have a spot, and others bleed quite a bit, even if they have been using tampons and such.

It varies from nothing to spotting for a few days. It's individual.