Alright, so there's some sins that CAN be committed and some which absolutely can not...
You may be referring to "venial" sins, which the just do commit, but these are called "sin" only analogously, as they are not against any commandment (that is, not 'contra legem') but are only at variance with, or not in accordance with, the law ('praeter legem'). They do not turn a man away from God, as mortal sin does. See St. Thomas, I-II q. 88 a. 1.
Look, you're obviously a good Catholic, and for all I believe a good Christian, but please, there is nothing about what you're saying I can agree with or relates in context to the scripture...I know where this, "You can lose your salvation" comes from, but it just does not jive with scripture and the logical conclusion of what Jesus did for all of us.
Do you realize Jesus is engraved with those scares we've given him for eternity...We can't even phathom the depth of hurt we must have given him, but because he LOVES us so much to put on MORTAL MAN forever, do ya think he would just give you up.
I'm sorry you believe this lie, and it's a lie that deceives good men and women into believing Christ sacrafice was NOT enough...
It's not about what YOU do, it's about what HE did.
If your interested, I'll show you as many verses as you like, in context, to try to get you to realize there is NO WORK you can do to lose you salvation.
Your emotional argument is not valid. One might as well say: "Scripture says that our Lord gave his life 'as a redemption for all' (1 St. Timothy 2:6) and 'God so loved the world, as to give his only begotten Son; that whosoever believeth in him, may not perish' (St. John 3:16). Do you think he would just give up? Therefore, all men are saved and no one goes to hell." That's just as valid an argument, and gives an equally wrong conclusion. God loves all men, and our Lord sacrificed Himself on the Cross to make salvation available to all. But only to those who "overcometh" will He "give to eat of the tree of life" (Apocalypse of St. John 2:7), as He Himself has solemnly promised in Holy Scripture. These are chosen by him in His own secret counsel, and were predestinated by Him before the foundation of the world. And not all the faithful are within this number, as Scripture testifies.
It is not a matter of our Lord's sacrifice being "not enough." St. Paul is clear: the justice of the law, "Cursed is every one, that abideth not in all things, which are written in the book of the law to do them. ... He that doth those things, shall live in them" (Gal. 3:10-12), is FULFILLED in "them that are in Christ Jesus, who walk not according to the flesh." (Rom. 8:1) How can one get past his absolutely clear words?
There is now therefore no condemnation to them that are in Christ Jesus, who walk not according to the flesh. For the law of the spirit of life, in Christ Jesus, hath delivered me from the law of sin and of death. For what the law could not do, in that it was weak through the flesh; God sending his own Son, in the likeness of sinful flesh and of sin, hath condemned sin in the flesh; That the justification of the law might be fulfilled in us, who walk not according to the flesh, but according to the spirit. For they that are according to the flesh, mind the things that are of the flesh; but they that are according to the spirit, mind the things that are of the spirit. (Rom. 8:1-5)
And St. Paul declares: "they who are in the flesh, cannot please God." (Rom. 8:8) If those who mind the things that are of the flesh cannot please God, and if "if you live according to the flesh, you shall die" (Rom. 8:13), then any Christian who does so after being justified does exactly that: he dies in spirit, and falls from grace. So it's not true at all that "there is NO WORK you can do to lose you salvation."