At about 1 PM I got severe lower abdominal pain, causing my to vomit back to to back, it lasted about 25 minutes.

A couple of hours later, I started bleeding but the abdominal pain was dull or non existent.

I recently got off my period, so I don't suspect its just an early period. Month ago I did take the Plan B pill on the 2 day.

Any ideas on what's wrong, if I should seek emergency services?

I wouldn't go to emergency, but I would go to your doctor. It could be a result of the Plan B though, that will muck things up something fierce. What kind of blood is it? Bright red?