Confused about what’s happened?

Yes, pregnancy is still possible, as the only emergency contraceptive pill that has been proven to work during the 24 hours surrounding ovulation, itself, is Ella (Ulipristal Acetate), & even that one isn't guaranteed to prevent pregnancy.

Plan B may work at that time, but it has not been proven.

You can see this on the Ella website.

It sounds like you mean you were on your 3rd fertile day, as, ovulation itself only lasts a matter of hours.
In your situation, I'd have opted for Ella, anyway, if available, as you probably wouldn't have known when your ovulation, itself, was due, & you'd have at least been very close to it.

I'm quite confused as to where you are in terms of your cycle, now, & when this happened. You say your period came on time, but you thought it was ovulation. Those two events happen at different points in your menstrual cycle, generally a couple of weeks apart.
Perhaps you meant that you thought it was implantation bleeding, not ovulation bleeding.

The only other option, is to have a Paragard IUD fitted by a doctor, within 5 days of the sex. That may prevent the pregnancy from implanting, if the emergency pill cannot help. That's if you still have time.

If you are outside of the 5 days, then you can only wait until you can do a pregnancy test. I have spoken to ladies who have still become pregnant, despite bleeding after the emergency contraceptive pill (some of them bleeding long enough to look like a period), so I would definitely advise testing when you are far enough along to get a reliable result.
You will probably not be pregnant, but best to check.

Assuming you're not pregnant, you will not know when you are due to ovulate/have a period, again, until your hormones settle down after Plan B, so best not to assume to know where you are in your cycle, until you know things are regular, again.

No you’re not pregnant. It’s also the effect of Plan B. It may make your period come early than the usual date or later than it, so it’s nothing to worry about.