Would posting ur own writing in 2-3 relevant clubs be considered spamming?

For me, as long as they're relevant clubs and the person isn't bothering other people to go read them/fan them I wouldn't consider it spamming no.

I have no problem with it. I usually post my fics on two spots; the show's spot and the character's spot.

I think it depends on the writing. If it's fanfiction which is relevant to all of those clubs, then it's fine. If it's an original story, it'd be better placed in a club like Writing. I've reported such articles as being misplaced in the past.

No, that is fine in my opinion as long as you're not spamming or begging everyone on the spot to go read it. :D it's content for the spot!

The keyword is "relevant".
As long as the clubs actually are relevant it's perfectly fine.