That's a really good answer from Lyn. I would add that "I worked from home" implies that the speaker didn't work in the office on that day. "I was working from home" doesn't have any connotation of that kind either way: so the speaker may have worked at home all day, or may have done some work at home and some in the office.

Hello! They are both correct. But these sentences could have a subtle difference. "Yesterday I was working from home" could mean that the person worked from home but that the work was not completed for some or other reason or that they worked from home yesterday but they are working from a different place today. "Yesterday I worked from home" could mean that the person worked from home and completed the job. "was working" is in the past continuous tense and "worked" is the perfect past tense which means that the timeline of the verb could be slightly different in the two sentences.

They are both correct, “was working” is essentially the same as “worked”.