Many years ago I heard a sermon at church. Later that day, while I was with my family, I said: "If God is God and Jesus is God's son, then what relation is the Holy Spirit?" I said it as a joke. After I said it I thought that maybe I had said the one thing that God said He would not forgive. I went deep into depression. I got so deep in my depression that I even started thinking about bad stuff and then thought, well, if I didn't say it then I didn't do it, but I thought something bad so I thought I've really done it now. It was as if my mind was playing tricks on me and trying to condemn me.
I talked to many people and read many things, but I guess I just never was totally convinced with the answers that I had heard.
I finally got over my depression. A lot of prayers and I John 1:9. But from time to time the issue and doubts will arise again.
I know that may sound minor, but I know that sin is serious to God no matter how us humans grade it.
It doesn't matter what I or anyone else might state about a passage. God's word contains what God means to say. It is up to us to comprehend those statements. "Knowing this first, that no prophecy of Scripture is of any private interpretation, for prophecy never came by the will of man, but holy men of God spoke as they were moved by the Holy Spirit" (II Peter 1:20-21). Nor is understanding what God has said an impossible task. "Therefore do not be unwise, but understand what the will of the Lord is" (Ephesians 5:17).
Your statement, while rash and immature, is not the same as what the Pharisees had done. They watched Jesus perform miracles on several occasions and then decided to tell people that Jesus was doing these miracles by the power of Satan. They purposely and defiantly chose to contradict plain evidence because they refused to accept that Jesus was the Messiah. This was true blasphemy.
You are right in one sense, sin is sin in God's sight and all sin leads to the same end: death (Romans 6:23). Though your statement was disrespectful, it is forgivable. Yet, Satan had a field day with you because he got you to doubt. "For whatever is not from faith is sin" (Romans 14:23). He convinced you not to seek forgiveness for a long while by convincing you that it wasn't worth the effort. He then got you to sin further because he convinced you that what is a few more sins on top of already unforgiven sin. Then he has you rejecting God's offer of forgiveness because he has you convinced that you don't deserve it. Can you not see the spiral that Satan has trapped you in? "And a servant of the Lord must not quarrel but be gentle to all, able to teach, patient, in humility correcting those who are in opposition, if God perhaps will grant them repentance, so that they may know the truth, and that they may come to their senses and escape the snare of the devil, having been taken captive by him to do his will" (II Timothy 2:24-26). Now, when people show you the truth, carefully giving evidence that it is consistent with the entire Bible, you turn away from it because Satan has you convinced, like Pilate, that truth might not be known (John 18:36).
God is not condemning you to Hell. ""Do I have any pleasure at all that the wicked should die?" says the Lord GOD, "and not that he should turn from his ways and live?"" (Ezekiel 18:23). You are making your own life a living hell by inclining your ear to Satan. If you end up in Hell, it is solely because you will have placed yourself there despite all of God's efforts to draw you back to the truth.
Have faith in God, "for he who comes to God must believe that He is, and that He is a rewarder of those who diligently seek Him" (Hebrews 11:6).
"Therefore submit to God. Resist the devil and he will flee from you. Draw near to God and He will draw near to you. Cleanse your hands, you sinners; and purify your hearts, you double-minded. Lament and mourn and weep! Let your laughter be turned to mourning and your joy to gloom. Humble yourselves in the sight of the Lord, and He will lift you up" (James 4:7-10).