sasha, i totally GET your frustration and feeling like it is all on you. any single parent, even if they work cooperatively with the estranged other parent feels it to some degree. you are not alone.
i remember clearly feeling like a cross between a sherpa and a soccer mom, always on the go to whatever the next "kid" thing was - or driving back over to her dad's with the "other" soccer sock....ballet shoe....school book. saying to myself all this stuff i HAD to do.....
and then it hit me. no, i am actually blessed that i GET to do all these things my child. i am blessed to BE a mom. i don't know if that helps you at all, but it was a like a bolt of lightening for me...........