Missed period but negative test?

So me and my girl friend had unprotected . The next day my girl friend got really freaked out and wanted to take the morning after pill. So she took the morning after pill and 4 days later she started to have some spotting. I read these where pregnancy symptoms and symptoms from the pill. 2 weeks later my girl friend started having her period earlier than expected. She also started to get really sick and started to have some soreness. We got really scared since all of these were pregnancy symptoms. We decided to wait for her period but its been over a month now since her last period, so finally we decided to take pregnancy test. The pregnancy test came out negative but she still hasnt had her period, is this normal?