hugs hun
you are not a crap mum- NOT AT ALL
you just had a crap day
had plenty of them- and they are normal to have
but today was a reality check for you today- all days arnt gonna be great
and we cant parent the way we want to all the time
some days you just have to write them off and know that you will start again tommorow!!!
get a swing for MR and that may give you another tool for the trick box
time to get some more tricks up the sleeve for Ms I as well
maybe start a reward thing with her- she is a smart cookie and will pick it up quick, just as she picked up the consequences thing quick- start small and work up- short attention - quick reward

Some days its about survival !!!!!!!! hang in there - and get some rest
know that i am just a phone call away- hugs