It can be very exhausting when baby wants to nurse all the time! But, there usually is a good reason! One reason your baby might feed more frequently is in response to sudden growth spurts. Babies can grow as much as 1.25cm in a 24-hour period. No wonder they need to breastfeed frequently for several days! Breastfeed as frequently as your baby indicates a desire. Your milk supply will soon catch up to the increased need. Giving bottles of formula at this time will only sabotage the natural supply and demand cycle, and you will be unable to catch up with your baby's needs.
In addition to growth spurts, some babies love to be held and nursed frequently as a way of helping them to adjust to life outside the womb. In fact, the first three to four months of life for all babies is a transition from the womb to the world. During "increased appetite" days, set aside other commitments to focus your energies on your baby. Sleep when your baby sleeps to recharge your system after these high-need periods. "Wearing" your baby in a sling or carrier may be helpful. Just as a toddler needs a periodic hug and kiss to make the world right again, a newborn may need to be cuddled and even nursed for a while.
As babies get older, they learn other ways of self-comforting, and breastfeeding sessions generally become shorter and less frequent. Don't worry...there will come a time when you will get plenty of rest! Believe me, you will miss the special bonding that occurs during these seemingly endless nursing sessions.