Hello. Thanks for posting your query at our health forum. If you re a healthy adult male, without any chronic disorders such as ( Systemic Hypertension / Diabetes ), then your penis size should be adequate. For most males, they suffer from this anxiety, and it comes in everyone s life, where they feel they are not able to satisfy their spouse/ loved ones. This leads to an anxiety and negative thoughts start creeping into their sexual life. There is no such approved treatment to increase sexual stamina. You need to be strong psychologically and moreover you have a daughter. If their was something wrong with your penis, then you would not have had a daughter, right? All I am saying is I personally feel your size is fine. Some people do have a little smaller penis compared to others. But if your erect size is around 10-15 cm range, then your size is good enough to enjoy a good sexual life. I will advise try taking like a couple of days off from your work. Spend some quality time with your wife. And when you are about to have sex, forget everything else, enjoy the moment. You will feel much better. Also i will advise you to take Tab. Evion ( Vitamin E supplement and anti-oxidants ), this will help in increase in sperm count and indirectly help your libido. You can also take a vitamin supplement like Tab. Cobadex once daily before sleeping. Have a lot of green vegetables, exercise regularly, follow a good life-style, and avoid smoking and alcohol. All these can have detrimental effects on your sexual life. If you want to clarify further doubts, you can put up more queries. And i will be glad to help you, Dr. Jaydeep