What symptoms are this?period?

my gf had symptoms such as sore and frequent white discharge that is different than the normal day. 3days ago she started to have mood swings. her las period was 4th january but till now still hasn't arrive. 5-6days ago she fell in sick for 2-3days. will that sickness cause the period delay?she took pregnancy test and came out negative with 2 different tester. its been 2 weeks after and she took the test, and is about 5days late of her period so she started to take the test.because we had on 28th january and 1st feb she started to have all the period signs that she normally have before her period start. so im confusing what happening to her