Je-li úterý a říkám, že do soboty jsem něco dělal / někde pracoval / nějak se cítil… – jaký bude správný čas?

Logicky by to měl být minulý, protože to období je pryč. Neměl by být ale předminulý když je tam nějaké trvání od někdy do Soboty?

I had worked there up until Saturday.

nebo jen

I worked there up until Saturday.

Nebo obojí?

(Chápu, že pokud bude výchozí bod někdy sobota-pondělí, tak by měl být předminulý. Ale pokud je ta výchozí situace DNES … – například – jsem unavená (v úterý) protože do soboty jsem hlídala děti, v neděli uklízela celý dům a v pondělí to byl mazec v práci… – tak co to hlídání dětí, když tam není ani znát kdy to začalo? – obyč minulost postačí, nebo se pletu?)

Za mě vše jen obyč.minulý

I agree with evaoslik. The simple past is ok. The past perfect is also ok, but it's not required: it just gives added emphasis to the fact that looking after the children until Saturday happened before cleaning the house on Sunday, but that added emphasis isn't needed. The continuous forms (“was looking”, “had been looking”) are also ok but are not required: they just give added emphasis to the duration of the activity (“looking after the children”).

• I'm tired today because (up) until Saturday I was looking after the children, on Sunday I cleaned the whole house, and yesterday we were really busy at work.
• I'm tired today because (up) until Saturday I looked after the children, on Sunday I cleaned the whole house, and yesterday we were really busy at work.
• I'm tired today because (up) until Saturday I had been looking after the children, on Sunday I cleaned the whole house, and yesterday we were really busy at work
• I'm tired today because (up) until Saturday I had looked after the children, on Sunday I cleaned the whole house, and yesterday we were really busy at work.

Similarly:

• (Up) until Saturday I was feeling / felt / had been feeling / had felt (a bit) under the weather, but now I'm right as rain.

děkuji