I feel your pain! I am absolutely exhausted, my oldest 5 are at school so I just have my 29 month old and 13 month old at home during the day but they virtually never nap at the same time so I'm on the go all day! Also my 13 month old still wakes at night so I don't even get a good sleep then
As someone else has said, I do find getting out for fresh air on the school run helps and wakes me up a bit, but I'm in bed by 9pm at the latest or I'm asleep on the sofa!