I’ve been re-watching my Prisoner:Cell Block H episodes, an Australian soap opera and they often use the phrase
“I did my block”
From the storyline, it must mean to go temporarily nuts or to get very angry.
As one person said “I did my block when I saw this bludger pinching my stuff.”
Meaning she got mad.
Is there any particular meaning behind this phrase? Or is it idiomatic? Or what?
Yep. “I did my block”: I got very angry; I lost my head; I lost my self-control; I “freaked out”.
“Did” as in: lost, destroyed, used up. “Block”: slang word for “head”.
Oh OK that makes sense, I’m used to hearing “blockhead” (ala Peanuts) as an insult so I would think one wouldn’t refer to one’s own head in that way. But that explinaton fits good
Thanks
Also, c.f. “If you do that again, I’ll knock your block off.”
Good to know: In American English, the idiomatic interpretation of that expression would be that the speaker has become very, ahem, friendly with the entire neighborhood.
That’s similar but not quite the same as the idea of your fanny hurting after rooting for your team for hours, to Australian ears.
Ah yes, “rooting”, always good snigger value.
I hear it more as “It did my block in” which meant: it confused me so much it made my head spin.
Like naming kids “Randy”. 
“I lost my block” and “I did my nut” are both similar phrases I’ve heard in NZ. “Nut” in this context also meaning “head”… not anything anatomically lower. To “nut” someone, as in “I nutted the cheeky bastard” is to headbutt – not to be confused with “kicked him in the nuts”… which in this case does not mean head. 
I’ve heard this from cockneys, so perhaps that’s a possible origin?
The most similar Cockney expression I can think of is “You’re doing my head in”, meaning “You are sorely trying my patience”.