What Causes Irregular Periods With Light Bleeding?

hi sir good evening , im raji 23 yearold gal. 5.3 feet 50kg now a days for the past 4 months periods are not exactly coming on date. and looking somewat pale compared to last days at my intermediate stage. and glow in skin reduced looking not good i.e not satisfactory. i work in a local tv channel as a newsreader and im preparing for competative exams. from the last 4 moths i stopped using cosmotics in make up. so please suggest me to regain my glowing skin as well as good healthy periods . please suggest thank yu