i have issues

I seriously wonder about myself sometimes. I have issues. I take the initiative and then spend the next however long wondering if it was the right thing to do, or if anyone else feels the same way as me... This goes for almost all areas of my life. Whether it be a decision that I need to make that haunts me for months and years for no reason other than I'm afraid of responsibility, or whether it be a simple matter of taking a leadership role within my friend group... I'm terrified. It needs to stop, but I don't know how to change something that's so basic to who I am.