O GOD, I can so relate to this problem. our schedule is somewhat like this:
7:30 wake up
8:30-8:45 -- 9:00-9:15 BF (one side) and nap
10:30 - 11 BF (both sides) and nap
1:00 - 1:30 BF (one side) nap
3:30 - 4:00 BF (both sides) and nap
6:45pm bedtime routine and BF (both sides)
7:30 pm to bed
my DD use to take a last catnap at 5pm which she dropped few days ago.
Yesterday I moved her bedtime little early around 6:30pm, she was still little tired but better than 7:30. She got up to twice to feed and other couple of times when I shh/pat her back to sleep and then I woke her up at 7:30am. Yes, she actually slept that long
DD is 5.5 months old now and EBF.
EDIT....
oops, that was before our new schedule is : started since yesterday
7:30 wake up and BF
9:00-9:30nap
11 - 11:30 nap
1:00 - 1:30 nap
3:00 - 3:30 nap
5:45pm bedtime routine
6:30 pm to bed
Today, I tried to put her for 5pm nap and VOILA, she is sleeping! but no guarantees for tomorrow
. hmm so I will goback to 7:30 bedtime today then.