I have to admit that the answer to that question for me is often "no." And why is that? I know I'm forgiven, for everything. And this is because of Christ's sacrifice. As scripture says:
...Jesus Christ,who gave himself for us to redeem us from all wickedness and to purify for himself a people that are his very own, eager to do what is good.
If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.
1 John 1:9
So, armed with that knowledge and experience, why is it that I still don't feel forgiven? I would argue that this is a tactic of the enemy of our souls to keep us from progressing in our faith. If we are having trouble accepting that we have forgiveness from all that blocks us from a relationship with God, then our default is to try and tear down those walls...ourselves. But this is no more than fighting the air, because the walls are gone -- we are forgiven!
But let's say we stay there, trying to do good in order to earn God's favor, or maybe just feel guilty a bunch. What's wrong with that? We'll probably accomplish some good deeds and maybe end up as better people.
But read this:
Anyone who rejected the law of Moses died without mercy on the testimony of two or three witnesses. How much more severely do you think a man deserves to be punished who has trampled the Son of God under foot, who has treated as an unholy thing the blood of the covenant that sanctified him, and who has insulted the Spirit of grace?
Full disclosure: I am taking that verse a little out of context -- it is written to folks who hear the gospel and reject it outright (see verses 26-27). But as I read it, it occurred to me -- when I continue to feel guilty, and then strive to earn my salvation through good works (or just plain feeling guilty enough), am I not doing this very same thing? Am I not "insulting the Spirit of grace?"
So what's the solution?
I did a little research and found a good article by Joyce Meyer on this very same topic. In it, she writes that, when we feel guilty for our sins, the first step is confession (see 1 John 1:9 above). Then, if we still feel guilty, she suggests speaking and claiming scriptures that confirm our standing in grace in order to combat those feelings.
Somehow it feels right for us to continually feel guilty for the wrong we do, as if each moment in self-condemnation takes one slash off the back of Christ and places it on our own. But the truth is that in maintaining this mindset, we are keeping ourselves in a state of slavery, like prisoners of war in a battle we literally cannot win...because it was already won by Christ.