I'll just pop in to give you one quick word of encouragement. Cluster feeding is normal, yes, and I found that when my DD cluster-fed in the evenings it meant a nice looooong nap afterwards, which also meant more sleep for me. Maybe see if she does go for longer after a cluster-feeding period, because if you know she's going to do that you won't feel as guilty about putting DD1 off for just a little while, when you'll be able to devote a nice block of time to her (leave the housework!).