What is happeneing here?
I just came across this phrase and want to make sure I know what is happening here.

eu tô numa loja

eu = I

Numa = em + uma (?)

loja = store

tô = ?

google translate say it means 'm what does it really mean?

Question

What is happeneing here?
I just came across this phrase and want to make sure I know what is happening here.

eu tô numa loja

eu = I

Numa = em + uma (?)

loja = store

tô = ?

google translate say it means 'm what does it really mean?

Answer

On the other hand, if you use "tô" when SPEAKING with a Portuguese speaker in an informal context (or even texting), you sound more fluent by doing so. (although this contraction is overlooked by orthodox grammar)

Answer

tô  actually is wrong use  ,the right  word is ESTOU ,but TÔ is used only in informal conversation , I advice you dont use Estou.
Eu estou numa loja.

Answer

tô = estou (short form)
eu tô = eu estou (i'm = i am)
numa = em uma = (in / at) + a

eu tô numa loja = i am in a store