"Feelings" are not what we should base our faith on. Faith is what pleases God, not feelings.
Hebrews 11:6 And without faith it is impossible to please God, because anyone who comes to him must believe that he exists and that he rewards those who earnestly seek him.
The passage does not say we must "feel" He exists, but we must believe.
Our sins are forgiven, the Word says so. Jesus died once for all our sins, past present and future, known and unknown.
1 John 1:9 If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.
This is the only place in the New Testament we are told to confess our sin. But this in mainly for our good, not to please God or to get righteous with God. We acknowledge we messed up, repent, and move on with our life. We do not need to dwell on our messing up.
We should be concentrating on worship, praise, and glorifying God, and recognizing how great He is. We can actually "glory" in our sin instead of exalting God and His goodness.
In the name of Jesus, I bless you with the life of God.