I'm extremely unfit to leave the house today. I'm okay within myself but looking after DS of 8 months is hard enough. He's walking, and I can't walk. If I do, I flood everywhere, despite heavy duty pads 
SIL thinks I'm ill with a vomiting bug (she saw me vomiting yesterday), but really I'm heavy bleeding from a miscarriage. We didn't tell anyone so I just want to keep it a secret.
SIL looks after our nephews (2.5 and 1 year) 2.5 days a week, for next to nothing so I understand she must be getting stressed. She's had them overnight recently because their mum is working away. Only happens twice a year when the work is there. SIL also has her own DC, age 8 and 3.
We all have a rota to walk our MIL's dog, since she isn't there during the day anymore for reasons I won't go into.
Today was my day. SIL messaged saying "Are you in London today?"
I said no, as I had to cancel. I'm still ill vomiting.
SIL "I was going to say, if you come and sit with the kids for an hour I'll go walk the dog"
I said that's fine, I was going to get a taxi there to MIL's.
SIL said "Ok" and then 5 mins later texted to say "Let me know if you feel better later and I'll go walk Harley as I need to pop to Iceland"
AIBU or is she being a bit cheeky? She thinks I'm vomiting.
Why would I want to go and look after another 4 children, 3 of which need their bums wiping?
It just seems off to me.
AIBU or is it a bit cheeky fucker?