Over mental stress,anxiety ,depression ,over protective mentality etc may be the cause of ur such dreams.If u have those above points then u must have to get rid off from them.u have to live a healthy life both physically and mentally . U can do it ur own by controlling over emotions ,busy urself on work,spending good times with friends and family,reading motivational books.If u cant do that alone then u have to consult psychologist online or offline and he will surely help u . Best wishes.