The girl had a lot prenancy symptoms.her date of periods was late.aftr 40 day she took her 1st prenancy test at home it came -ve. and got periods. why?

Irregular period: Many symptoms of early pregnancy are the same as the symptoms girls have before their period starts. Nausea, bloating and breast tenderness can be pregnancy symptoms OR premenstrual symptoms. There are many reasons for periods to be "late". Normal cycles can be anywhere from 28-40 days long. For women who typically get a period every 4 weeks, stress or other factors can cause late periods.