What Causes Hair Loss And Irregular Periods?

I am 25 yrs old female married. (Height 5.3", Weight 51.5) My periods not regular before & after marriage. In Periods my body aching & flow only 3-4 days. My Periods are Painful. I have Hairfall problem. In May Skipped period. In June I have done Pregancy test ( Urine Test), but its negative. after that now I am taking Deviry Pills for 5 days. Yesterday is 5th Day.