Many times, in working with (primarily) young men contemplating a priestly vocation, the big sturggle is with a sense of unworth. 'How could God call me, a sinner?'
Well, let's look at St. Paul's life:
Murderer, of a sorts: (participated in the martyrdom of St. Stephan)
self-righteous (best of the Pharisees)
Rash and brash
with the above, we could surmise an arrogance and a cocky-ness, too.
And he is the Aposlte to the Gentiles
So, if you think your sins are greater than God's call, in simple words: get over it. God still loves you, do you love Him back enough to give it all over and say yes, despite your flaws, sins and weaknesses?