A baby who doesn't sleep!

What is the recommended number of hours of sleep for a 5mo baby? My baby sleeps about 12 hours on good days, which is rare! In fact, she barely meets the 12 hours frm 3mo up to now. Stress, stress! Hope that's not the contributing factor that my baby is not really growing ;p Weight - 5.6kg, Height - 62.5cm & HC - 39cm