Is she pregnant? Or is this from Plan B?

So my girlfriend and I had sex on April 26 and the condom broke. This was about 3 days I believe after ovulation so she took the Plan B pill within 2 hours. Her period was due May 6 and it wound up coming May 7 for her regular 4 days. Her symptoms have been light headedness, dizziness and she even spit up blood a few times so I don't even know if these associate with the pill or pregnancy. Her period was due yesterday June 2 and she hasn't gotten it yet. She said she experienced cramping on the 1st but she hasn't cramped since. Today she said her back hurts but she believes she pinched a nerve because she hasn't felt that before in the past month. I hear Plan B can mess up a cycle but I'm trying to find an answer to just clear my mind of this. Was her period last month because of the pill or could it have been her natural period since it was only a day late from her actually date she was supposed to get it?