To what extent do the works Antigone and The Great Gatsby show that an individual is in control of his or her own destiny?

The two works have very different attitudes towards destiny because they are grounded in different philosophical and religious beliefs.
Antigone is a play based on Greek mythology. Sophocles did not invent the story but rather retold a commonly known account of the travails of the Theban dynasty, perhaps adding or modifying some details but generally following earlier sources. The main action of the play results from a curse on the Theban dynasty caused by Laius, father of Oedipus, who angered the gods. This curse then affects Oedipus and all his children, as well as the city of Thebes as a whole. Thus, while Antigone and Ismene can make limited choices about how to respond to their situation, their destiny is determined by the gods. The Greeks believed that no one, not even Zeus, could escape fate or necessity.
The Great Gatsby is a novel about a self-made man in twentieth-century America. The background is secular, but there still is a sense of heredity determining fate, as Gatsby—despite his willpower and intelligence—never quite manages to join the upper-class society of East Egg; in the end, he remains an outsider.