hello, First of all, you need to undergo one blood test for beta hcg to confirm pregnancy. Early home pregnancy test is less significant. In exclusion of pregnancy, other reasons are hormonal imbalance, ovarian cyst, stress, over wt/ obesity, irregular diet, psychological factors, thyroid problem etc. Following blood test, you need to consult with gynecologist to proceed other investigation like USG scan, thyroid profile etc. Take suggestive measures accordingly. Take healthy diet, reduce body wt by regular exercise, avoid stress by yoga or meditation. Be well.