I think loads (if not all) of us Mums feel that way at times... it's never-ending and very hard work. I just have the 1 son (15 months) but have been single since pregnant so have done it all on my own (have not slept in in years). If it wasn't for daycare I would not be able to cope at all.
Do you know what I think? I think it's the sever lack of support we have these days.... no-one helps! They're either too busy or live too far away. Furthermore, women don't seem to support each other enough either, even though we're all going through it ourselves. Just look at how many of us come on to this forum just for a few words of support/encouragement/validation.
It was hard on my nanna's generation because although they had 'the village', they didn't have choices, and often had unsupportive husbands and unhappy marriages. It's hard on Mums today because we have impossible expectations put on us and are expected to do it all like superwoman and enjoy it! The cost of living is so high now that for many Mums, work is not an option let alone flexible work arrangements.
There's nothing worse than knowing full well you need to make some changes in your life to better it, yet being too tired to bother. If you're a single parent of centrelink benefits then you can be eligible for JET assistance in which the Government will cover the childcare costs. Perhaps look into this for starters so you can get a break for a day or two a week. This will give you more energy to think about what best to do to make some changes. x