A question about sin

Another thread about blasphemy got me thinking about sin.

Apparently there are two types of sins. The first are against Jesus and are OK because they're forgivable but the second are against the Holy Spirit and those are not forgivable and condemn the sinner to eternal damnation no matter what they do to try to put it right. The Catholic Church says you can be forgiven through confession which goes against the unforgivable bit. The Protestants get round it by saying that to be forgiven and unforgivable sin would be a miracle and as God can do miracles he can forgive you. I find this a bit confusing. Would anyone like to clarify it?

As lying, stealing, murder, adultery, not keeping the Sabbath, coveting your neighbour ass and a myriad of other things are also sins do you get upset about all of them or is there a hierarchy amongst sins?

Do you never, ever tell a white lie to spare someone's feelings? What about Santa? Is he a white lie? Is a white lie less of a sin than any other coloured lie?

Do you never, ever go into a shop, garage, hotel, restaurant or anywhere else that someone is working on the Sabbath? Is it a sin to work on the Sabbath or because it's a rest day? Is it OK to work on the Sabbath if you have a rest day on another day? What about doctors, nurses etc? Are they committing sins for working on a Sabbath?

You may not have coveted your neighbour's ass but have you never fancied his Jag or Land Rover?

St Thomas Aquinas said that despair is a blasphemy against the Holy Spirit and therefore can never be forgiven. Seems like I'm buggered then.

This isn't a facetious question btw? There just seem to be so many sins and yet people only seem to get upset about a few of them. What about the Leviticus sins? Do you avoid pork and bacon? Or not wear pearls? It seems that as Christians you don't have to follow the OT rules so why are the Ten Commandments still accepted? And what about the poor guy with the crushed scrotum or chopped off penis who commits a sin by going into a church? I kid you not it's in Deuteronomy 23:1

Didn't Jesus just give three commandments. Love God. Love one another. Love yourself.