Yesterday I didn't go to work, because I was ill. Please free to correct if neccesary. Thank you

It makes sense to me, but I don't have a grip on the periphrasis ir+a+verb. To me if ** voy a trabajar=I am going to work** then fui a trabajar=I was going to work, but that may be too anglicized.

I was going to work yesteday, but I was ill.

I think that you could also say:

Ayer no fui al trabajo porque estuve enfermo. (if you feel fine today-began and completed in past)

Yesterday I didn't go to work, because I was ill. Please free to correct if neccesary. Thank you

Hi, poliglott, your Spanish is getting better by the day.

tu frase es correcta. En España no diríamos "me enfermé", sino me puse enferma, me puse mala, no me encontraba bien...pero tu pasado es correcto.

Quentin:

I am going to work: voy a trabajar
I was going to work: Iba a trabajar

I went to work: fui a trabajar

The last sentences is not the periphrasis, but the ver ir + direction a

voy a la escuela/fui a la escuela

Trabajar is , as you yourself said, to be taken as a noun.

Heidita thank you so much for your kind words. It's all trial and error, we are all so honoured to have such wonderful teachers like you