If it makes you feel better I experience barrages of these horrible thoughts every single day, some more than others. All I can do is ask for forgiveness, that God would close off all doors to myself permanently and cast these thoughts as far as possible from me and replace them with His Presence. God has been helping me, and it encourages me to know others are going through it.
John Bunyan also went through the SAME thing and he writes about it in his book The Pilgrim's Progress:
"A very great storm came down upon me, which handled me twenty times worse than all I had met with before. It came stealing upon me, now by one piece and then by another. First, all my comfort was taken from me; then darkness seized me; after which whole floods of blasphemies, both against God, Christ, and the Scriptures, were poured upon my spirit, to my great confusion and astonishment.
They did so overweigh my heart both with their number, continuance and fiery force that I felt as if there were nothing else but these from morning to night within me, and as though indeed there could be room for nothing else. I also concluded that God had, in wrath to my soul, given me up to them, to be carried away with them as with a mighty whirlwind. Only by the distaste they gave to my spirit did I feel there was something in me that refused to embrace them.
While I was in this torment, I often found in my mind a sudden urge to curse and swear, or to speak some grievous thing against God, Christ His Son, or of the Scriptures. Now I thought, surely I am possessed of the devil. At other times, I thought I would lose my mind; for instead of praising and magnifying the Lord with others, if I but heard Him spoken of, presently some most horrible blasphemous thought or other would bolt out of my heart against Him. So whether I did think that God was, or again did think there was no such thing as God, no love, peace or gracious disposition could I feel within me. These things did sink me into very deep despair, for I concluded that such things could not possibly be found among those who loved God.
In these days, when I heard others talk of what the sin against the Holy Spirit was, then the tempter would so provoke me to desire to sin that particular sin that it was as if I could not, must not, neither would be quiet until I had committed it. Now no sin would serve but that one. If it were to be committed by the speaking of such a word, then it was if my mouth would have spoken that word, whether I would or not. In so strong a measure was this temptation upon me that often I have been ready to clap my hands under my chin to hold my mouth from opening. To that end also I have had thoughts at other times to leap with my head downward into some muck hole or other to keep my mouth from speaking."