Help!

I'm new at this with 2 hives.

Checking one of them this afternoon I noticed lots of brood in my lowest
supers and I have been using a queen excluder.

Couldn't find the queeen - haven't been able to find her since I got the
hive - but assume she is doing her job because the hive has increased in
size very well.

I have 2 medium supers on the hive and brood is only in the first(lowest)
one and the brood chamber.

The only thing I can think I might have done, maybe is put the excluder in
the wrong place and queen got up.

Now what do I do!!!!!!

fred
crystal river, fl
2 hives - amatuer