Hi! I'm 18 years old and I only have my period twice a year. I first had my period when I was 11 years old, the first two years of my period was normal, but when I turned 13, my period became irregular and have it twice a year only. Asked a friend about this and she told me that my hormones might be changed because I had an anti-rabies injection. I also went to an obgyn last year, they gave me pills that I drink for 2 weeks, they say my menstruation will go normal if I drink it but nothing happened, and I'm taking herbal medicine today given by a therapist and hoping that my period go regular again. Why is my period irregular? Can I do something about this?

The reasons your periods are so irregular are numerous and no one online can give you an absolute reason why they are so. I would schedule another appointment with your obgyn and let them know it didn't work and to do more extensive testing.