Help needed with simple phrases please!

Help needed with simple phrases please!
 

Hello :)

I have a question concerning some really simple phrases which Im not sure if I say correctly...

For example :

Usually I eat porridge for breakfast - Usualmente como gachas de avena para el desayuno --- or --- Usualmente desayuno gachas de avena. Would both options be accepted?

And : There was thunder and lighting last night - Anoche hubo trueno y relámpago. Or would it be more correct to say : Anoche hacía/hizo ?

And one more: Our bookshelf broke down last week - Nuestro librero (or estante para libros- which is better?) se rompió en la semana pasada. And our bookshelf is broken - Nuestro librero está roto. - Is this correct?

1. "Usualmente desayuno..." sounds better than your first option; instead of that one I'd prefer "...en el desayuno" or "...para desayunar".

2. I'd prefer the verbs: "anoche tronó y relampagueó" or "anoche hubo tormenta eléctrica" (much better).

3. "Librero" and "se rompió en la semana pasada".

Gracias :) So I should never put "en" when talking about the past? what about.. it will break on the next week... romperá en la próxima semana?

I didn't say never, but the emphasis on the idea of "one occasion during that period of time" is superfluous here. "En _(unit of time)_ pasado(a)/próximo(a)" makes some sort of pleonastic sentence, as you already defined which period of time you're talking about.

Understood. Thank you:)

And a note on your English:
To my US English native speaker ears "Our bookshelf broke down" is very strange. A bookshelf can break, collapse, and fall apart, but it cannot break down.

Sorry, I meant just "broke" :)

It's wrong to use in both languages.
It will break next week.
It broke last week.