Does your OH help a lot?
My DH works long hours in the week and is exhausted come the weekend which I understand, he needs some down time too. I think our situation would be different if he had a regular 9-5 but some days he won't get in from work till 2am.
Come the weekend, I'd love some help from DH but childcare is seen very much as my "job" and I'm tired and need a break too. I'm also pregnant which is adding to the tiredness. We argue EVERY weekend about who is more tired and who should have a lie-in. Unless we have something absolutely concrete in the diary like visiting friends or something, we don't get out as a family because DH says he's tired and sleeps on the sofa all day. If I ask (beg) him to give me a break then he does pull his weight - but I shouldn't have to ask!
I'm just fed up and sad.