Hello,
Here, you need to undergo one
blood test for beta-hcg to rule out product of conception or
miscarriage. TVS scan gives some additional information.
Other reasons of irregular period are stress/ anxiety,
hormonal imbalance,
pelvic infection, over wt, irregular diet pattern, uterine pathology etc.
Consult with your gynecologist for proper examination & relevant investigations. Take suggestive measures accordingly.
Practice safe sex in future. Good luck.