A baby can become easily overstimulated.
When baby becomes overstimulated the baby will find it difficult to settle.
This may be caused by lots of visitors in the early days, too much play time, or stimulation by mobiles over sleeping places, etc.
When a baby is overstimulated this then results in the baby becoming overtired. When a baby gets over tired he will cry, scream and become very distressed and so will you!
Very young babies can really only stay awake happily for around 30 minutes. If the baby has become over tired and over stimulated go and sit somewhere quiet and dark, holding baby close and patting/rubbing gently on their back.