Considering that I am correct in stating God's Will is perfect and the things that happen in our day-to-day lives are all a part of God's Will, how does that include the people the reject God?It is important first to distinguish between the "active" and the "passive" will of the Lord. Those things that come as a direct result of the action of the Lord are the product of his active will. God said, "Let there be light" and there was light. Those things that come as an indirect result of His action are the product of his passive will. The rejection and subsequent eternal damnation of some men is the result of God's passive will.
How can people reject God but yet God's Will is still done through them, due to everything is a part of God's Will, or is God's Will still done through them?
God wills that man have the free choice to accept Him. Thus, the ability of man to freely choose God (as opposed to being forced to choose Him) is a product of the Lord's active will. However, a consequence of this ability to freely choose Him is the reality that some men may end up in hell for freely rejecting Him. This is still a part of His will because it exists within a paradigm that He willfully created.
Furthermore, theologians make a distinction between what the Lord wants or desires, and what he wills. As it pertains to this topic, although the Lord may desire that all men be saved, He wills that some may not. This is because He wills that man have the ability to freely choose Him, and the consequence of that is that some may reject Him. An every day example of "want" vs. "will" is a father who desires never to have to spank his child but who still does so when it is in the best interest of the child.
To this some may wonder, "If it is obviously better for man that he end up in heaven, why doesn't the Lord just force every man to accept Him?" To that I say, "Because that is not Love." God IS love, and love, by its very nature, implies free assent. Any relationship that is forced upon another person is not a loving relationship. And so, it is because He loves us and because He wills, for our sake, that we love Him too, that He has given us the ability to freely choose (or reject) Him.
Finally, note that, while Catholics rightfully acknowledge that eternal damnation is an object of the Lord's passive will, we also assert that God actively damns no man (as "double predestination" would hold). God gives to every man the opportunity for salvation. For more on predestination, go here.
I hope that answers your question.