Yes, and no. First to the no. Theologians, who like to make distinctions, distinguish between God’s communicable attributes and His incommunicable attributes. The former are those which He can and does share with us, though of course in lesser degrees. God, for instance, knows things and we know things. He, however, knows all things and knows them exhaustively and we do not. The latter refer to those qualities that are His alone. God, for instance, is immutable, while we are not. He cannot change, and we do in fact change. If ever there were an incommunicable attribute, however, it would be this- God is self-existent and eternal. We assuredly are not. God alone is self-existent and eternal, and all other things are dependent upon Him. Are we then creators in this sense? Of course not. I’m confident as well that your pastor would agree.
We are, however, God’s vice-regents, the stewards of His creation. And in calling us to exercise dominion over the creation, to be fruitful and multiply, to fill the earth and subdue it, He is calling us to reflect His glory, to be images of what He has done in the creation. As we bring all things under subjection, by His power and for His glory, as we the church act as a helper to our husband, the Second Adam in His call to bring all things under subjection, we enter into His work with Him. In this sense it would be fitting to say that we are “co-creators with God.” I suspect that your pastor had something like this in mind.
That said, there are at least two different groups that are terribly confused on this issue. Prosperity preachers have been known to teach what has come to be known as the “little-gods” doctrine. These folks, many of whom glut our airwaves, suggest that just as dogs have puppies and cats have kittens, so God begets little gods. This ancient heresy is explained and answered well in a fine book titled The Agony of Deceit, edited by my friend Dr. Michael Horton.
The second group is the eastern Orthodox church with its doctrine of theosis. Here salvation is less about our being declared just by the finished work of Christ on our behalf, and being adopted into God’s family, and more about how God’s grace is poured into us, making us partake more fully in the divine nature. You can read more about theosis in any dictionary of theology.
It is important for us to keep always before us, not just touching on creation, both the similarities and differences between us and God. The classic doctrine of our being made in the imago dei gets it right. We affirm the imputed dignity of man when we remember that we are made in the image of God. We escape the temptation of the Serpent when we remember that we are made in the image of God. We are neither cosmic accidents, nor gods. We are men, made in His likeness, for His glory. I trust, once again, that your pastor understands this as well. Always listen as a Berean, but always listen with a judgment of charity.