I apologise in advance for any bad language but I am so angry.
I have just settled youngest DC to sleep after OOH GP visit.
Due to one DC being in hospital atm and DH looking after the others while trying to shuffle work hours the littlest went to stay overnight with my aunt (who is, for all intents and purposes my mother). I called at midnight by prior arrangement.
I hear DD crying, really distressed, in the background and of course ask what's up. Since late morning DD has had a temp, then been progressively ill and had pee problems and passed blood the last few times - not once was this mentioned to either me or DH when we called through the day, when I spoke to DD (2) was just told she felt a bit hot and then she was distracted telling me happily about lunch and playing with the dogs - as she sounded quite perked up by the end I put it down to rushing around like a mad thing with the dogs and needing her nap.
I was told how poorly she was so flippantly, like it was no big thing and she would sleep it off. Not only had we not been told (as 'No need to worry') but they hadn't taken her to the GP, walk-in centre - nothing. Not even a call to NHS direct even. She's had no pain relief at all either to try and get a handle on her temp and stop it hurting.
Fuck knows what they were going to do, if anything, as we weren't due to pick her up until this evening once other DC discharge had all been sorted.
So then I was in a position of either DH leaves the DCs at home and tries to find childcare at midnight or I leave the hospital and hope DC sleeps through which is unlikely. However he's safe there so I let the nurses know and off I go to try and sort out the baby. Get to GP, unsurprisingly she has a hooching uti, gets dosed up with calpol etc and first dose of abs then we get home and try to settle her down.
I didn't really say anything when I collected her as was a bit overwhelmed at their attitude but said would call in AM.
Now I'm just gobsmacked and fucking livid and can't express quite how I feel about it - I've got terrible guilt that my poor baby was so miserable for so fucking long and we weren't there and that my poor DS has probably woken and Mummy's nowhere to be fucking found. I'm probably disproportionately worried about DDs kidneys as she's pissing every 2 minutes but I have no idea how much fluid she had as she's been vomiting as well from a mixture of temperature, distress and infection 
feel shit that I've put her in that position in the first place and want to tear strips off my aunt and uncle for leaving her in such a fucking state and not saying a fucking word.
To top it off DH is unhappy with what has happened but is counselling a bit of assiduous toungue holding until I've calmed down and then talking through what went on before making any rash decisions or saying any hasty words. How can he be so fucking sensible? I know IABU to want to bang their heads against the wall but I don't think IABU to ask wtfff they were fucking playing at.
I think I'm struggling with his view that family harmony is more important than wanting to know why our daughter has been left ill and in pain and wtf they think would have happened if I hadn't found out? She had a febrile convulsion in the surgery and we were poised to go to A&E if her temp hadn't come down so had to wait with a poorly child at the surgery to be re-assessed.
Fuck.
right, sorry it's so long and sweary, it does feel better to have got my rage written down but I am honestly baffled and at a loss as to what to do and still want to shake DH and shout 'why aren't you as angry as I am???' I'm back off to the hospital now so apologies for any delay in replies as busy day to come and DS is not a good sleeper. Thank you if you got this far. I assure you I'm not as terrible a parent as this makes me out to be!