It happens. Once a month usually 😉
Ease your concerns. You said you wore a condom, so minimal chance of catching anything.
And as you sound worried, I assume you immediately freaked out and scrubbed yourself clean in the shower too, much to her embarrassment.
Fwiw, the vast majority of girls are clean and disease free. You might get some itchy cock or a UTI now and then. Nothing that a bit of doxycycline won't clear up.
But look - All girls bleed. All girls can give you an itchy cock or UTI. If you like fucking, menstruation is something to get used to. It's only a bummer if it's your sheets, for which I recommend fucking in the shower.