Pregnant or Early Menopause

My doctor told me my postpartum periods would be regular no later than 1yr postpartum. I’m 13 months postpartum now.

My past 3 cycles were all 25 days apart. Before I got pregnant they were 25-31 days apart. Now I’m 14 days late. I took a pregnancy test at 10 days late and it was negative. I’m starting to think this is early menopause. I’m 42yrs old. I was told late bloomers are more likely to experience early menopause. I hit puberty a few months shy of 18yrs. Am I crazy?