Wow, I could have written this when my boy was that age. I think this is normal. My boy wanted to eat all the time. It a growth spurt. THey have small tummies. Once empty, there hunry again. One doctor I went to told me that If I feed my baby every hour, I will get sore nipples and they will get damaged, that I should let him cry until at least 2 hours before I feed him again. So I switched doctors. I always had a little problems breastfeeding, but you know what, my baby is now 17 months and I am still b-feeding. When he was 4 months I decided to put him in his own room, b/c he was always waking up and wanting to eat. Then instead of feeding him, I would put a pacifier in his mouth. He hated the pacifier and would cry a little, but I refused to wake up anymore and 3 in the morning for feedings. Well it worked and til this day, he still sleeps throught the night, except when teething.
I hope this helps.
L.