fed 5 month old wakes every 2 hours to nurse!!!?

My fed baby wakes every two hours to nurse at night. He eats veggies for lunch and oats for dinner ( I always offer the first ) . He doesn't take a pacifier and he co- sleeps. He has a good feeding of milk b4 bed ( nursing). He is 19 pounds. I don't think this is normal at his age. If I try to rock him he cries and we tried to let him cry it out but it didn't work. Any advice is appreciated!!