God said if we confess our sins he forgives all sins?

It's saying that everyone is forgiven for everything, period.  God doesn't hold anything against anybody.  The problem with that kind of love, unconditional forgiveness and reconciliation is that if you don't want to accept it, you refuse the forgiveness, it does you no good. You remain where you were, eaten up with guilt in a prison of your own making, a hell created by you.
 In other words, God's forgiveness is no good if you won't accept it.  You remain "unforgiven"

There should be no difficulty in understanding.  Every sin EXCEPT blasphemy against the Holy Spirit can be forgiven.  

Blasphemy against the Holy Spirit is where God draws the line.

Hannah J Paul

Where did you get the idea God said if we confess our sins he forgives all sins?  He didn't.  He said the sin of blasphemy against the Holy Spirit is unforgivable. 

Without faith in the means of forgiveness, no other sin CAN be forgiven.

The Holy Spirit is the voice of conscience, calling us to repent of our sins. Once we reject His influence in our lives, we can no longer repent of our sins, therefore no longer confess them, therefore no longer be forgiven for them.

"And so I tell you, every kind of sin and slander can be forgiven, BUT blasphemy against the Spirit will not be forgiven". (1John 1:9) (Generally speaking if we confess our sins God will forgive us, except there is no forgiveness for those who blasphemy the Holy Spirit. (Matthew 12:31)

You have to conscientiously  deny God to blaspheme the Holy Spirit.

The latter sin only happened in one time and place.  Therefore it cannot be duplicated.  Mt. 12, Mk. 3.

This is a difficult and controversial subject. The vast majority of people do not even know anything about "blasphemy of the Holy Spirit" and they go about their daily lives. Most people also do not think about assigning the work of the Holy Spirit to that of Satan. And most people are not "self righteous" Pharisees. That was the specific scenario and is the essence of the unforgivable sin to which Jesus was referring. 

Some theologians have suggested that the unforgivable sin is rejecting the work of the Holy Spirit to bring a person to faith in Jesus as Lord and Savior. However, I take that as a "given". Reject Jesus, go to hell. Period. That is not necessarily a "blasphemy", it is a rebellion. And it isn't that it is not forgivable, it is that forgiveness was rejected and cannot be rescinded after death. To which I say - choices, decisions, consequences. 

In Matthew 12:32, here is what Jesus said, "Anyone who speaks a word against the Son of Man will be forgiven, but anyone who speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come." Both Jesus and the Father have taken direct action to influence our lives, inserting their Persons in the process. Their actions were manifested with events that sparked controversy - such as the great flood that killed everyone, save for eight souls, or when Jesus whipped and drove the moneychangers out of the temple. Perhaps God understands that not everyone can approach those controversial events with wisdom but instead foolishly rail at God for them. 

The Holy Spirit is unique in that He is a Helper and Comforter and always quietly goes about God's purposes in subtle ways, doing nothing that can be defined as controversial, but instead good, caring, and loving. Therefore, for a person to target the Holy Spirit with blasphemies is the ultimate in targeting the Person of God and reflects a profound hatred for God. I can see that as fully aligning one's loyalties with God's enemy Satan and thus casting one's "fate" in stone and consequently being unforgivable. And it is not that God proactively condemns the person but that He no longer seeks to bring that person to repentance. He has thus permanently "shaken the dust off His feet". Recall that Jesus said, "No one comes to Me unless the Father draw them". No draw, therefore no salvation. No salvation, therefore eternal punishment.

Will God forgive me?: https://www.jw.org/finder?wtlocale=E&docid=502015256&srcid=share
What is the unforgivable sin?: https://www.jw.org/finder?wtlocale=E&docid=502016103&srcid=share