I recently came to know and agreed with my friend that i realize my own mistakes but when i try to overcome them i fail and keep repeating those same mistakes unknowingly and then later i realize Oops i did it again. And when i fail i blame myself for being good for nothing. And then i blame myself for all the failures in my life. Is it Normal, what should i do?

but then I thought, so what if I did mistakes?
The only thing that matters is that I don't hurt anyone, (emotionally and physically.) All else is secondary.
I found that the mistakes that I made against others, are forgotten by the people who I wronged, while I still dwelled on them on and on. I got tired of always thinking about the mistakes I've done. And when I actually do think of them with an open mind, they don't seem so serious of mistakes anyway.
At the end of the day, it is up to you to deal with things. Make truce with yourself before you make truce with anyone else. When something is bothering me, I resolve it before the day is over so I can sleep with a clear mind, if I couldn't address it that night, then I drop it the moment I step to bed. My friend told me that advice and my god, it changed the way I deal with so many things.