Will Stress Lead To Irregular Menstrual Cycle?

Hi.. I'm working in night shifts from past 3 yrs. I 'm having irregular cycles lately from past 1 yr.. like around 7 to 8 months i did not have a single cycle and i did consult a doctor for that. Later i started getting cycles normally for 2 months and now it's not stopping at all.. from 1 month and 1 week continuously it bleeds and looks like it'll stop and suddenly it increases. i'm getting some lump like discharges regularly.. Need some help on this.. is this alright.. am i suffering from some severe problem ?