From your story and the number of larvae seen, my money would be on Laying Workers. This will be confirmed (or not) in the next few days, just as soon as those cells are capped. If they are capped with domed (bullet-shaped) heads - then you have a Laying Worker colony. If flat(-ish) - then all is well.
In the meanwhile, if you can get hold of a magnifying glass, take a look in the cells around those larvae - if you can see eggs in them, then they could be used to speed-up diagnosis.
LJ