So my cleric, Kathra (5e level 17), was transported to a world where her God doesnt exist. I am a female dwarf and a religious fanatic of Berronar Truesilver. Even if there was a similar dwarven God in Eberron, which there isnt, Kathra would NEVER accept an embassador God.

I am wondering how to handle this. Since a clerics magic comes from faith,  im assuming i can still cast spells? Especially since my faith is the central trait of my character. Or is my magic lost? Can Berronar be reached from Eberron? Why or why not? Do the other Gods forbid it, or.is it flat out impossible?

Will I have a faith crisis or will.I try to bring my faith to this.new.world? It depends.on how i am able.to relate to my God now. I am at  loss.on the rules of this, therefore on how to move one.

Any.advice.ON RULES mucj appreciated. Thanks 

This is going to be a DM question. 
In general by RAW, it doesn’t matter what plane a cleric is on, they can typically access their spells.
However, also by RAW, eberron is sealed off from the other planes — it’s not really supposed to be possible to go there from somewhere else and vice versa, and outside gods aren’t supposed to be able to exert influence there.

The end result is, your DM is homebrewing this situation, so you’re going to have to ask them how it works. I’d guess that figuring that out will help answer most of your questions. 

I was not aware tht Eberron was completely sealed. It is to my understanding it is on its own material plane that is compromised of the astral, ethereal and shadow planes. Therefore, Eberron would just be another plane, correct? So in theory i could plane shift in and out? Why or why not? My God should be able to also, since I have planar shift, but she is probably not interested that much in me or is forbidden to by Eberron pantheon? Or am I missing something. 

Also, great that my spells work, but I have a doubt regarding Divination and Divine intervention, where contact with my God is direct. If she is not there, I wonder if those two work, and if so, how they could work

I also understand that Eberron is accessible through a portal in a flower shop named the Queens Kiss in Cormyr. How would that make it completely sealed off? Or is this seal only inactive at the portal site?

Very curious for answers on rules

From chapter 4 of the current Eberron book:

Eberron is part of the Great Wheel of the multiverse, as described in the Player’s Handbook and the Dungeon Master’s Guide. At the same time, it is fundamentally apart from the rest of the Great Wheel, sealed off from the other planes even while it’s encircled by its own wheeling cosmology.

How your table chooses to interpret “sealed off” is up to you, of course. As is the option for it to not be sealed off. But you asked for the RAW.

Part of the gamble of playing cleric is adventuring where their magic doesn't work because their God has no power there. That's why some people play arcane spellcasters, because that drawback doesn't apply to them. Remember seeing that explained in some adventures, something like divine spellcasters such as clerics and paladins can't access their class features while they're in this region, because the power of their gods and beliefs don't interact with their surroundings the same way they did before.

Our cleric tried to cast a high level spell while in the temple of another god.  A voice rang out "Not in my temple maggot"   I have always played that if the cleric could not contact their deity they could still cast granted spells but would be unable to replace them.