My Girlfriend Has Not Seen Her Period Since January. This

My girlfriend has not seen her period since January. This happens sometimes as she has the condition PCOS.
Just to be sure we took a pregnancy test on the 3rd of April and the results were negative.
Yesterday and today she has had sharp pains in her abdomen. This is followed by a feeling of loss of appetite, dizzy nauseous feeling and the feeling of want to throw up. What is going on with her? Please help