Crazy thought... God knows the sins we'll commit in the future. That means that if He was gonna let us go for doing something wrong that He would have done it before it happened because He already knows about it. I think human understanding has trouble comprehending (at least in my mind) that God doesn't let us go just because Satan makes us feel guilty and says He does.
"For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:
Not of works, lest any man should boast." ~ Ephesians 2:8-9 (KJV)
God's grace doesn't give up and make us work for our way into His favor just because we do wrong. If that were the case Jesus would not have died on the cross to completely erase our sins if we trusted in Him, would He?
It's really amazing that no matter how bad I am that God still loves me.
Does it still hurt Him and my relationship with Him when I sin? Yes! If I ask Him to forgive me then will He? Undoubtedly, yes!
"If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness." - 1 John 1:9 (KJV)
Does that mean I can sin and know I'll be forgiven no matter what? Yes, but why would I want to do that when God has been so good to me - Me, who is so unworthy of His love?
"What shall we say then? Shall we continue in sin, that grace may abound? God forbid. How shall we, that are dead to sin, live any longer therein?" - Romans 6:1-2 (KJV)
We should leave our sins behind and run for what we know (between us and God) to be truly right.
"Wherefore seeing we also are compassed about with so great a cloud of witnesses, let us lay aside every weight, and the sin which doth so easily beset us, and let us run with patience the race that is set before us," - Hebrews 12:1 (KJV)
God's grace is so amazing and honestly until you've experienced it deep down and personal within yourself then you can't sing Amazing Grace How Sweet The Sound and actually feel the gratitude towards Jesus in your heart!
So no matter what doubts we have we should push them aside and just run towards Jesus no matter who tells you He isn't there for you anymore!
God is a righteous and just God and His promises are true!
"for he hath said, I will never leave thee, nor forsake thee." - Hebrews 1:5 (KJV)
All I can recommend is the same thing that God recommended in the Bible. Put on the armour of God because your doubt is Satan's way of attacking you spiritually. Yeah, he's real cunning and you'll think it's not him but Satan is the master of deceit and only Jesus can fully protect and make you able to stand against him in the day he tries to bring you down.
So I'll end it with these final verses that are key to staying strong in Christ Jesus!
10 Finally, my brethren, be strong in the Lord, and in the power of his might.
11Put on the whole armour of God, that ye may be able to stand against the wiles of the devil.
12 For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.
13 Wherefore take unto you the whole armour of God, that ye may be able to withstand in the evil day, and having done all, to stand.
14 Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness;
15 And your feet shod with the preparation of the gospel of peace;
16 Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked.
17 And take the helmet of salvation, and the sword of the Spirit, which is the word of God:
18 Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints;