I just canned for the first time!!!!!

I made applesauce and canned according to Blue Ball Preserving book (or whatever it's called).
About 15 minutes after I took the jars out of the hot water bath I heard two 'pops' from two different cans. I've not found anything about this, but I can't imagine it's good. Does this mean those two jars aren't going to seal?????
Also, I 'simmered' too many of the jar lids. Will the ones I simmered but didn't use be ok to use a different time, or will that not work??