Premature ejaculation(PE) is not uncommon and depends on multiple factors , the most common being psychological factors like stress , anxiety, depression which can be due to personal, professional , financial and other social issues which one deals with each day. The other factors that potentially lead to PE can be organic like diabetes, hypertension, hormonal imbalance, trauma etc.
Based on your description, it seems likely to be more of a stress and anxiety issue and try to be little patient and realistic in terms of performance expectation. A good psychological and physical health will help you most. You are suggested to undergo routine blood work (blood sugar, urea etc) and health check up at a clinic and consult a Physician if the problem worsens. Avoid or cut down on alcohol if at all you take it and watch your diet as well.
I hope it helps. Take care and regards.