I’m sorry it took so long for me to answer this question. It was one that I needed to wait to make sure I could really give some thought to.
I would say I’ve been there. I would say that struggling with the same sin(s) is a shared experience. And I would say that if you feel out of place in the church… well, it’s taken me forever to feel comfortable with that too. I will say this though, love is the answer. I know it’s cliché, but love drives out fear, and fear is a common root in everything you mentioned. Fear that your belief is not enough, fear that you will never overcome your sin, fear that you can’t "fit in" in church. But God is love, and he knows what you’re going through.
When doubting, proclaim with the man from Mark 9:24, "I do believe; help me overcome my unbelief." When you realize you have sinned, confess it, confide in a friend believer you trust (James 5:16; we were meant to bear one another’s burden, not handle everything individually; Galatians 6:2).
if you are doubting your salvation, remember what is required of you–which is of course, very little. God does the saving work. Your job is to place your faith in him, confess him as Lord, acknowledge that he is your hope. Nothing you can do will earn your salvation, not even working yourself into an emotional frenzy about your salvation. If you believe, you believe. His grace is sufficient. 1 John 1:9 says "If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness." Should you keep doing the same sin over and over? Well, no–you flee the temptation. You work with other people (shocking, I know). Jesus has enough strength in his shoulders to carry you even when you sin that "one more time" — we’d all be screwed if he didn’t. Work out your salvation, but remember it’s really God’s work (Philippians 2:12).
Whatever you do, don’t give up on the Church. You need it and it needs you. If you find a perfect church, don’t go, because you’ll mess it up, but search for a church with at least a handful of humble people that are loving. Even if they aren’t your "type," give them a chance. They might surprise you–first impressions are rarely the best.
Grace and Peace be with you, Anonymous.