Thanks for using healthcaremagic.I understand your concerns. Brief answer: Anxiety,depression,relationship issues,excessive masturbation,androgen deficiency,and drugs are the frequent causes. Detailed answer: If i were your physician,would initially assess for any psychogenic cause,as it is commonly associated with sudden onset of sexual dysfunction like erectile dysfunction(ED),premature ejaculation(PME) and then try to find and rectify other physiological causes like any recent drug consumption history,vascular causes,hormonal deficiency etc causing the problem.I would also advise you to avoid smoking,alcohol(also causes ED,PME)and to seek the help of a psychiatrist,who can solve your issues with psycho-pharmaceutic therapy if needed or direct you in the right path. Hope this information helps you.If any further questions,happy to answer you.Take care.