Hey, Rachel, I'm glad you decided to stop by. We may not answer your question, but we'll discuss it to death

First off, you may be interested in 1 Tim 1:13, in which Paul says "Even though I was once a blasphemer and a persecutor and a violent man, I was shown mercy because I acted in ignorance and unbelief."
You may also be interested in a similar verse, seemingly out of nowhere in Ephesians 4, (verse 30, to be exact), which says "And do not grieve the Holy Spirit of God, with whom you were sealed for the day of redemption." What? He's talking about purity of speech in the passages before and purity of action in the passages after. More on this in a moment.
Some things I have read suggest that blasphemy of the Holy Spirit is a sin of the
tongue (hence the juxtaposition above with Eph. 4:28-29, an injunction to not let anything unwholesome come out of your mouth). Blasphemy is spoken and, therefore, a spoken sin. This is definitely supported in Scripture, with the phrase "speaks against." But I would suggest that blasphemy would start in the soul and the mind, far before any words come out. This is sort of supported in verse 25 of that Matthew passage, where it says that Jesus saw what they were thinking. Therefore the blasphemy will first manifest itself spiritually (verse 30) and then verbally (verse 31).
With this interpretation, it can be argued that one who has blasphemy in his spirit is unpardonable not because of some shortcomings of divine mercy but because the blasphemous soul is unrepentant. With this view (taken by some commentaries), the very fact that you believe and are concerned about this is good proof that you are not unpardonable. Blasphemy of the soul may be equated to other Biblical phrases such as "hardening of the heart," and if your heart is honestly seeking then I don't think anyone would call it hard.
I hope some of this helps