Under my feet
In the way; "Since he's been retired, I can't seem to get on with my work like I used to - under my feet all day he is!"

Under the doctor
A delightful local expression meaning under the doctor's care; "'E've been bard alright - 'e've been under the doctor this ages, but I think 'e's coming now!"

Under the weather
Not feeling too well

Up all night
Having had a disturbed night; "Up all night I was - with fidgetty pains in my legs.... !

Up together
Well organised, as in ".... you wouldn't take them for sisters - one's a bit wit-wat and the other's always up together."

Up to the mark
(a) When you don't feel 'up to the mark' you are not as well as you might be, although the cause is probably not clear.
(b) Up to the expected standard, as in "These pillow slips are not up to the usual mark, but they know how to charge for them!"