He welcome to health care magic forum. Brown spoting and cramps and irregular period suggest, infection, So i suggest you to consult a gynaecologist for diagnosis and treatment, otherwise same thing may continue for succeeding periods and there can be other side effects of it.
You may need to use medicines, for controle of the infection. Anaemia
is also a cause of the brown spoting and irregular periods
Besides i advise you some diet recommendations as take more of green leafy vegetables, pulses, sprouts, milk, egg, meat, and sea foods to provide iron and proteins
necessory to build up blood.
Wishing for a quick recovery and thanks for calling.