Haven't had period in months but bad bloating and tender breasts, why?

Many possibiliites: !st, ifyou ahve skipped periods then you shoudl check a pregnancy test immediatly. There are many other reasosn for skipping periods that mostylky involve ovulation disorders such as thyroid, prolactin or pcos. Your bloating may be a sign that you need a progesteroen withdrawl bleed. Mastalgia (breast tenderness) is likely due to hormonal fluctuations, but most important to se eif you are preg.

Irregular menstrual : You might want to check a pregnancy test. If it is negative then you should see your primary care physician.