If someone carries with them a longstanding doubt throughout their entire life, regarding if they can be saved. Do they have enough faith to be saved?

If someone carries with them a longstanding doubt constantly throughout the entirety of their life, regarding if they can be saved. Do they have enough faith to be saved? This applies to me personally, and I would love to hear your thoughts. Is there a difference between faith and belief? And in my personal context I think there is a relatively small chance I have blasphemed against the Holy Spirit, and if true, I would be unforgivable. If I carry with me the belief that there is a small chance I am not saveable, do I really have enough faith to be saved?