I don't believe that a truly saved person can lose their salvation for anything. The only unforgivable sin is blaspheming the holy spirit, which, no truly saved person would ever do. It's not something you do by accident. It's a conscious act.
People who resort to taking their own life are in a state of mind that is not sane. As a result, you have to ask yourself if they are responsible for their actions at that time.
Many who have attempted suicide have been treated and moved on to very productive lives.
Christians are not punished for their sins, we are seen pure as the whitest garment as we are washed in Christ's blood. However, we will be tried by fire and many will be found lacking. This, to me, means that a person who is saved but just by having one foot in the door so to speak would have no rewards but they will have eternal life. Where as someone like Billy Graham, for lack of a better example, would have crowns and rewards for his fruits here on earth. Someone like Paul Bundy, who apparently accepted Christ before his execution, will have no reward other than salvation from eternal spiritual death.
In Revelation we see various congregations of believers. Only two aren't in deep danger of losing their lampstand/Menorrah, figuratively the Light of the World. One is told, for example, that they have "lost their first love." I.e. they did love Messiah at one time but now have grown cold. Nowhere are we told that just because Messiah paid for our sins that we can live anyway we like, now. Actually we are more obligated, therefore, to live a life of obedience to Him.
We are told that "those who persevere to the end will be saved." There's some perseverance needed fella, not just saying, "Yeal, I accept you as my Savior, now I don't have to do anything" or, as some people seem to feel "And I can do anything I like now because my sins have all been paid for!"
We are also told of some who have "tasted the Heavenly gift" but then go astray and that there is therefore no more atonement for their sins.
We are told "Many will call to me in that day [Judgment Day], Lord, Lord" i.e. they think they are believers -or, I guess I should say they think they are His followers, for "even the devils believe and tremble". They will claim they have done this and that for Him. But He will tell them "Be gone from me you workers of lawlessness. I never knew you."
If someone does make it to Heaven just barely we are told that "Some will have no reward" there. So, yes, we do have sins forgiven if we are truly His follower and persevering in trying to be obedient, therefore. But those who have been the most obedient, who "heap up treasure in Heaven" will have the most rewards and some will have no reward at all.
Praying for you for wisdom in this area.