Given the data you've provided (irregular cycles, overweight and hair growth) ... you could be experiencing poly-cystic ovarian syndrome (PCOS). Hair growth, or "hirsutism", is often due to this type of endocrine disorder. During PCOS, the ovaries produce more male hormones (androstendion) that cause hair-growth, obesity and menstrual disorders (lack of ovulation). Hirsutism during PCOS is followed by symptoms of virilisation (clitoris growth, breast atrophy, voice changing, irregular cycles, obesity etc.). If there aren’t signs of virilisation, hair growth can be considered a skin disorder and treated by a dermatologist but if there are additional signs of virilisation (as in your case) you should visit a gynecologist-endocrinologist for further help.