Yeah, even after so so SO many litters...losing one is still a downer. It really is...but your first litter is extra special so it'd be even more devastating. Do your best, know you did your best...and hope for the best!
My first litter was unexpected. Not because I wasn't intentionally breeding...but because I was too dumb to ask the previous owner (who, after many years is still a good friend of mine) if she'd previously been with a male...she had, and was pregnant when she arrived. I didn't notice the signs of pregnancy as I figured she was just putting weight on after the move (again, stupid me) and I came how to a body strewn cage
It was a nightmare and after (nearly) 9yrs, it still sticks in my mind. Period. Four bodies about the cage, one teeny tiny kit in a corner hiding under the cage feeder...nightmare.
Anyhow, you can only do so much and even if you do everything you can some just don't make it. I've had feisty kits one day, dead kits the next. Newborns go downhill QUICK and there's a "point of no return" ask any breeder...we know when the kit isn't going to make it...you don't want to let it get that bad and you always have a hard time deciding when to intervene to avoid that point. Too early and you could cause milk to stop flowing, mastitis, nursing issues...too late...well...
Anyhow, keep us updated. I hope all goes well and you get to enjoy the super specialness of your first litter.