It sounds to me like the “enemy within” (the “flesh” …the “old, sinful nature you were born with”, see Psalm 51:5 and John 3:6) and the “enemy without” (the Devil, who loves to tempt believers to sin) are very active. Yet there is a “way of victory” which we shall see in a minute. Before we do consider that, I hope you realize that this is NOT “blasphemy against the Spirit” (commonly known as “the unpardonable sin”). You can read about this in Matthew 12:22-32 where you will learn that blasphemy against the Holy Spirit involved UNBELIEVERS attributing the works of the Holy Spirit to Satan. In other words, they were “speaking evil of the Holy Spirit” by calling Him Beelzebul (i.e. another name for Satan). As you said, you are not actually SPEAKING out loud words against the Spirit, so you are not guilty of this sin. Basically, the “sin against the Holy Spirit today” is the “sin of UNBELIEF” by rejecting the gospel of Jesus Christ that the Holy Spirit is preaching to unbelievers so they will be “convicted of sin” and brought to “repentance toward God, and faith toward our Lord Jesus Christ” (Acts 20:21). Those who reject this message are RESISTING the Holy Spirit’s testimony of Christ. The first Christian martyr (Stephen) told his murderers in Acts 7:51, “You men who are stiff-necked and uncircumcised in heart and ears are ALWAYS RESISTING THE HOLY SPIRIT: you are doing just as your fathers did” (NASB). The very fact that you are CONVICTED of your blasphemous thoughts shows you are a true BELIEVER who feels bad that such thoughts come to mind.

What is the way of victory? I would encourage you to read slowly and prayerfully Romans 7:14-24. In this passage the Apostle Paul rehearses the experience he had of trying to please God by keeping the Law of Moses and yet he kept “sinning against God” repeatedly. The things he wanted to do to please the Lord he WAS NOT DOING and the things he did not want to do he WAS DOING (verse 15). At some point he made a discovery; he discovered that the “old nature of sin” was still within him (verses 17-20). All along he was “trying to please God in HIS FLESH (his own human, yet sinful, nature) and he was met with DEFEAT. Yet he goes on in Romans 8:2-4 to learn that he had “the way of victory within him,” not through THE FLESH, but through the HOLY SPIRIT. “For the law of the SPIRIT of life in Chrit Jesus has made me free from the law of sin and death. For what the law could not do in that it was weak through THE FLESH, God did by sending His own Son in the likeness of sinful flesh, on account of sin: He condemned sin in the flesh, that the righteous requirement of the law might be fulfilled in us WHO DO NOT WALK ACCORDING TO THE FLESH BUT ACCORDING TO THE SPIRIT.”

What Paul was essentially saying is if we TRY to defeat the sinful nature in us, WE WILL BE DEFEATED, but if we TRUST the Holy Spirit to set us from free from sin WE WILL BE DELIVERED! The next time these blasphemous thoughts come to mind you must realize, “Okay, this is coming from my sinful nature.” You must, as another has said, “Take no notice of them whatever, as by doing so you give the flesh the place it seeks. Go on as not hearing the suggestions—be as it were deaf to them. Confess to God if you find YOUR WILL at work, but not so as to be occupied with the analysis of evil; rather look up to Him (the Lord)…in the attitude of dependence of soul, pass on with your eye resting on Him, out of whom strength comes whenever there is conscious weakness” (John Darby from a tract titled, “Unwelcome thoughts unbidden”). If you will immediately turn to the Lord in real dependence on the Holy Spirit who dwells in you (Romans 8:9-13), He WILL give you the victory as we see in Galatians 5:16-18, “I say then, Walk in the Spirit, and you shall not fulfill the lust of the flesh. For the flesh lusts against the Spirt, and the Spirit against the flesh; and these are contrary to one another, so that you do not do the things you wish. But if you are led by the Spirit, you are not under the law.”  (DO)  (689.3)