My sheep hear my voice, and I know them, and they follow me. I give them eternal life, and they will never perish, and no one will snatch them out of my hand. My Father, who has given them to me, is greater than all, and no one is able to snatch them out of the Father's hand. John 10:27-29
Welcome, Young Believer! This is one of those questions that has divided the church into separate branches based on doctrinal differences. According to Catholics, Methodists, and Eastern Orthodoxy, the answer is yes you can lose your salvation. I'm sure there are a few other groups out there that I've missed, but since that's not the doctrinal camp that I'm in I really can't list all of them for you. This disagreement between the churches is so strong that those of this first camp believe that those in the second camp that believe you cannot lose your salvation are heretical and vice versa. What do the branches who believe you can lose your salvation have in common? They also believe that you must earn your salvation on a basis of good works and therefore can lose your salvation because of works.
Now the reason I can say confidently that you absolutely cannot lose your salvation is because we believe that our salvation comes by faith alone through grace alone in Christ alone. Good works are not a requirement to be saved but a result of the work of the Holy Spirit in us transforming our lives. Bad works are also known as sin is covered by Christ's death for us on the cross, this doesn't just include the sins pre-salvation but also the sins post-salvation.
And every priest stands daily at his service, offering repeatedly the same sacrifices, which can never take away sins. But when Christ had offered for all time a single sacrifice for sins, he sat down at the right hand of God, waiting from that time until his enemies should be made a footstool for his feet. For by a single offering he has perfected for all time those who are being sanctified. Hebrews 10:11-14
The obvious question you may be asking at this point is, what about all those people who are deconstructing their faith and walking away from God entirely? I would say that is a very reasonable question to ask, but I would counter with, why do you think those people were saved, to begin with? Having a knowledge of God, the religious concepts of Christianity, and regular church attendance is not what saves you. If you listen to the stories of people who are deconstructing and walking away from Christianity as a religion they all acknowledge that while they may have had a spiritual experience at some point they either do not know the foundation of the Gospel or deny its validity entirely. In other words, they never were saved and they are not being unsaved by walking away from the religious practice and self-identification as a Christian now.
“Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but the one who does the will of my Father who is in heaven. On that day many will say to me, ‘Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many mighty works in your name?’ And then will I declare to them, ‘I never knew you; depart from me, you workers of lawlessness.’ Matthew 7:21-23
Note that Jesus even says that there will be people who perform "acts of power" such as prophecy and casting out demons in His Name that come before the judgment seat and He will say, "I never knew you..." He did not say, "I knew you once, but I no longer know you."
There are also members of the "Christian" community who will tell you that because you're not experiencing blessing because you are suffering through illness, poverty, persecution, etc... that you are clearly not saved. This could not be more false! Your salvation is not reliant upon your circumstances and cannot be taken from you by the challenges and suffering you may face in this life.
Who shall separate us from the love of Christ? Shall tribulation, or distress, or persecution, or famine, or nakedness, or danger, or sword? As it is written, “For your sake we are being killed all the day long; we are regarded as sheep to be slaughtered.” No, in all these things we are more than conquerors through him who loved us. For I am sure that neither death nor life, nor angels nor rulers, nor things present nor things to come, nor powers, nor height nor depth, nor anything else in all creation, will be able to separate us from the love of God in Christ Jesus our Lord. Romans 8:35-39
I want to encourage you my brothers and sisters in Christ to have confidence in your salvation knowing that it wasn't by any act of your own that you could be saved but that it is because of God's relentless love and grace for us. Again not because we are worthy of this grace, but because our perfectly just and righteous God is also perfect in His love and mercy. For His glory we are saved and by His righteousness, our debt of sin is paid. Can a debt once paid be owed again to the debtee? No!
Blessed be the God and Father of our Lord Jesus Christ! According to his great mercy, he has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead, to an inheritance that is imperishable, undefiled, and unfading, kept in heaven for you, who by God's power are being guarded through faith for a salvation ready to be revealed in the last time. In this you rejoice, though now for a little while, if necessary, you have been grieved by various trials, so that the tested genuineness of your faith—more precious than gold that perishes though it is tested by fire—may be found to result in praise and glory and honor at the revelation of Jesus Christ. Though you have not seen him, you love him. Though you do not now see him, you believe in him and rejoice with joy that is inexpressible and filled with glory, obtaining the outcome of your faith, the salvation of your souls. 1 Peter 1:3-9
If you have more questions about whether or not you can lose your salvation please place those in the comments. I also highly recommend, as always, that you find a mentor in the faith that will help to walk you through these issues as you grow in your faith. This is one journey you were never meant to take alone!