This is how we obtain salvation.
If you declare with your mouth, “Jesus is Lord,” and believe in your heart that God raised Him from the dead, you will be saved. - Romans 10:9
One you become born again can you ever become unsaved?
If we have to believe in our hearts that God raised Him from the Dead to stop believing and turn away means we have back slidded. Back sliders will face a worse fate because we know yet reject.
Will Christ forgive me for all of my sins?
He died for all of your sins. "But he was pierced for our transgressions, He was crushed for our iniquities" - Isa 53:5
When we confess and repent He forgets our sins. We become white as snow meaning blameless.
“Though your sins are like scarlet, they shall be as white as snow; though they are red as crimson, they shall be like wool. - Isa 1:18
Every day we confess and seek His mercy and forgiveness for any transgression we have committed. God is not us. We hold grudges and at times refuse to forgive, and walk around with this chip on shoulder thinking people owe us. Sometimes so vain that we think that when people talk and laugh they are referring to us when the person(s) may not be even thinking about us. Conjuring stuff that are not real. God on the other hand is merciful and it endures forever! He is faithful. He is loving. He is constant He does not change.
Will Christ ever stop loving me
"Who shall separate us from the love of Christ? Shall trouble or hardship or persecution or famine or nakedness or danger or sword?" - Roms 8:35
"For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers,neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord." - Roms 8:38
God is love He cannot hate He will never stop loving us even if we disobey. He may not be pleased when we go against Him but He will not stop loving us.