It is highly unlikely that we're made out of stuff from only one star. The simplest reason for this, is that we have gold on earth. Gold is (we believe) created by the collision of two massive stars (neutron stars probably).
If there was only one predecessor to the sun, it would be extremely likely that all of its mass would still be nearby. The total mass of the entire solar system is much to small to have formed for example nickel and copper in any noticable amount. You would have to have a star of about 5 times the mass of the solar system. That mass doesn't go away.
You could, of course speculate that a couple of neutron stars at 2-3 times the solar system initially created everything, then split up into around 2-3 different solar systems. But we have quite a lot of chemical elements such as hydrogen and helium in the sun, which there would not be a lot of in neutron stars (due to it having to have fused into heavier elements).
All stars go through a few stages from their inception to their death:
Initially, the theory is that hydrogen was the prevalent chemical element. It's the "simplest" chemical element. When helium is compressed, due to the gravity of a star it's temperature will rise up. Once it reaches around 10 million degrees, fusion starts. Fusion of hydrogen creates helium.
Helium, being heavier than hydrogen will sink to the center of the star. Later, you will have helium fusion, if the star is massive enough to compress helium enough. Helium will generate oxygen and carbon.
A very massive star, multiple suns in mass, is able to fuse oxygen and carbon - which creates a lot of different chemical elements; neon, sodium, magnesium, sulfur and silicon. Later reactions transform these elements into calcium, iron, nickel, chromium, copper and others.
Eventually, many stars will explode into a supernova. In that process, a lot of these materials will be ejected into space, where they will gather due to gravity again.
The sun was probably created in a messy universe, where hydrogen and perhaps helium came together in a region where there was a lot of these other chemical elements.