Two questions:
1) What source books are you allowed to use, by the way? (not that there are many 0 and 1st level spells in other books as it is)...
2) Does "loosing everything" include loosing material and focus components or do you still have your holy symbol and spell component pouches?
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Well, some helpful ones, though this list may need to be adjusted depending on your answer to the above:
0:
Cure Minor Wounds - great if you want to keep someone from bleeding to death but don't really need them to be healed back to positive hit points right away) -- though, no need to prepare since it can be spontaneously cast.
Create Water - if you are low and food, rations, general supplies in addition to weapons and all...
Detect Magic - need new stuff? Great way to sort through the treasure loot. Though, if other spellcasters already have this prepared, no need to be redundant
Guidance - 1 minute duration. If your cleric is the cooporative sort cast on fighters (or yourself) and what not before a fight (or other activity). A bonus (however small) to a roll can make all the difference in the world, especially when you are all low in experience and low on resources (weapons, armor, etc.).
Light - if without torches and know you are going into a dark place ...
1:
Bless - same reasons as guidance and it affects more people
Cure Light Wounds - staple necessary, though, can be spontaneously cast so no need to prepare
Doom -- if, and only if, you have a really good DC then perhaps this. But, since you are so limited in spell power right now, I'd avoid spells that get a save and just go with the personal buffing ones... but, still, if you have a good DC on your spells, then this is a good one (makes it harder to hit your quasi-naked bodies

)
Shield of Faith -- (if you have the M) when without armor, find ways to boost it
Summon Monster I -- (if you have a divine focus) if you all can't handle much, any little help will get you through a lot!
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Some others have possibilties but depends a lot on where you are, what you plan on coming against, etc... lots of combat or social stuff, cave/dungeon or wilderness, expected enemies, etc...
Anyway, that's just my two cents... you may want to still get back to those two questions above as the answers to those will influence the suggestions you get ...