You live under grace, you are His child and heir.
As wyguy says, stop beating yourself up! All satan has to do when we do beat ourselves up is step back and move on, because he has done his job.
This feeling of unworthiness you have is directly from the pit of hell. You are worthy in God's eyes, so worthy His Son died for you. Every time we beat ourselves us we chip away at the Cross upon which our God and our sins were put to death. We in reality, put Him to death over and over when we do this. And none of us want that do we?
Throw yourself at the foot of the Cross, and tell him you cannot do this by yourself, and hand yourself over to Him.
Surrender yourself, not the parts of yourself you feel you should.
We can't surrender part of ourselves, because the part we do not will always override that which we have "surrendered". And we end up in limbo.
Blessings