Hi there!
I heard a theory about this, based on the fact that Genesis 1 doesn't describe the actual creation of the earth, as an object, only says it was formless and empty.
The idea is that life on the earth may have been destroyed once before, as it was in the Flood, but with no survivors. There was nothing left, only the bare, unformed earth, a sort of shapeless blob perhaps, covered by water.
This is pure speculation, as has been said, and I don't think it a very likely interpretation. But its possible I suppose...
Like life on other worlds, God would have told us, if we needed to know, but He didn't, so we don't - none of our business!
But, if it worries you, the best thing is to seek the Lord about it. Ask Him for a specific Word to your heart, that will settle this thing for you, once and for all.
Probably He won't settle the business by giving you a yes or no answer to your question, but He WILL give the answer you [i]need[/i].
It sounds like your pastor is (maybe not deliberately) sowing confusion among his congregation with these ideas.
Perhaps you should pray about finding another church?
Bless you as you seek His Face
Jeannette