Yep. The main reason for doubting your salvation is looking at yourself for assurance. Whenever you do this you will find none, unless you are deluded by self-righteousness. None of us are as holy as we should be, or as repentant, or as committed, or as faithful. We all fall short of who we should be in Christ, each in our own way.
I am certain of my salvation. Why? Because I look to Christ and I know he cannot fail. He died for my sins, he was buried, and he rose again on the third day (1 Corinthians 15:3-4). He took the wrath of God in my place for my sins, rose again, and credited his perfect righteousness to me (Isaiah 53). He said that he came to do the will of his father, which is that none of his people will be lost but all them will be raised at the last day (John 6:37-29). He said that none of his sheep will ever perish (John 10:27-28). I stand justified because of his righteousness, I stand forgiven because of his sacrifice (2 Corinthians 5:21). It is all about him, so I look to him for my assurance and NOT to myself.
Look to Christ and his finished work on the cross. Look to his perfect life and his perfect righteousness, his perfect sacrifice and his resurrection from the dead. Look to him alone for your assurance, and you will never be in lack of it.