Considering there is already an exhaustive answer going through the various meanings of plus on this site I will only try to clarify the meaning of the sentence in OP's question:
Puis moi, je me suis retrouvée avec... plus beaucoup de vision.
I Plus de...
First let's point out this is spoken language, it is correct but colloquial, other ways to express the ...
"Plus beaucoup" means "not much any more", or "not any longer" (Macmillan).
In the present usage,
the Wiktionnaire calls this word an adverb, but the TLFi calls it just a particle.
"Plus" is a tricky word as it can be an adverb of quantity, a preposition that has the meaning of addition, and finally a negative particle
Tu vas encore te perdre is the normal unstressed way to say it. But you are right encore could be placed after the verb to create an effect.
When writing I would introduce a coma before encore.
Tu vas te perdre, encore.
and when speaking make a pause before encore.
Having encore after the verb shows insistence or exasperation.