Hi there...erectile dysfunction could be due to many reasons. Anxiety being the most. So first try relaxation techniques and distraction method. Then try to cut down on any habits like alcohol, smoking or drugs. This will help prolong erection. If there's no improvement then you must be investigated for any comorbidities like diabetes hypertension hypercholestrolemia. Since you are telling you have cholestrol, that could affect, but it is not hugjly significant. However treating these comorbidities also can help. So consult a general physician for that. Medically there are many options like oral medications and topical creams available which can help. If the above conservative measure do not help kindly consult a psychiatrist or general physician for medical therapy.