I remember a few month ago that was very angry with God and testing him if he was real because at that time I was a new Christian and I was feeling a complete different person. I was kind of doubting God existence and I didn't know much about the bible and I attended church a few times. I remember blurting out something against the holy spirit when I was angry which I regret. At the moment I feel something different or thing change. I didn't know there was a sin. So far lately I haven't feel god in my presence or my holyspirt instead I keep on hearing my own voice of my head that I was going hell for committing that sin, I'm no longer save, or god isn't going to forgive me for that unforgiving sin or I will always feel guilty of that sin. I was thinking about going to back to my old life because I know that God will never forgive of that sin I committed and I will foreverly be lost.
Blasphemy against the Holy Spirit is attributing something to God that is evil,when God is good,like saying God does not love me,or God is punishing me,or God is responsible for natural disasters,or problems on earth,or He does not care about me,and the such,or God will not forgive me,but some people do it out of ignorance,not understanding,for a lot of people in the world are confused as to how God really works in the world,and might attribute something evil to Him out of ignorance.
But being mad at God,and you were worried about it,I do not believe would qualify,for God knows that the problem is with you,not Him,and He does not give frustration,and any mental disturbance,but a sound mind,and also you were new to the Christian lifestyle,doubting,with worldliness still lingering around,and basically wanting answers,before being iron clad in your walk with God,so God would take all that frustration,and confusion,you have into account.
I do not know the extent of seriousness that blasphemy is,for it would seem like some people that do attribute something to God that is evil would be able to be off the hook if it is done in ignorance in certain circumstances,for it would be hard to believe that blasphemy can be done by every person that ever said they were mad at God,because they can be frustrated,confused,and not thinking normally,and rational.