Going by the definition of micropenis, you do not fall in that category. A penis that is smaller than 2.8 inches in length is called a micrto penis.
You have only asked us about having sex, what about urinating? Are you able to pass urine standing up? This problem is noticed during childhood. It happens due to insufficient levels of the male hormone, testosterone.
You have asked a one line question. This indicates the depression that you are going through. To a man his manhood which is his penis is a great concern to him. It is believed that 1 in 200 males are affected by this condition. But there are no statistics on the subject. Often the treatment at birth is the change of gender from male to female. But this is not done at present as it is treated as child abuse.
These days there are some procedures in Surgery that can help. I advise you to seek expert medical opinion.