How to proceed after forgetting to include time-when/location/adverb phrase before main verb?
It's totally valid and common to add adverbial modifiers after your main clause.

In conversation, rules are breakable. In writing, there is 倒裝句(Inversion), yeah, that means putting adverbial modifiers at the end of the sentence is grammatically correct, if you follow the inversion rule.


  I'm living in Chicago (pause) Well only currently.


我住在芝加哥, 呃, 只是目前


  We're watching TV (pause) At my grandmother's house, that is.


我們正在看電視, 在我奶奶家.


  I donated some chairs (pause) Which was yesterday actually.


我捐了些椅子, 昨天捐的.

People usually say something like this in my hometown:

你做什麽了, 昨天?

What were you doing, yesterday?