This is an important question.We need to rely on the authority of the scriptures to teach us of salvation and to assure us of our salvation after we have believed on the Lord Jesus.A few verses that tell us how to be saved are: Acts 16:31, John 3:16, Romans 10:9-13, Philippians 2:5-8.We need to rely on these verses if we ever question the fact of our salvation.What do the scriptures tell us we need to do to be saved?According to these verses (and others) it tells us to put our faith in the Lord Jesus Christ.If we have done that, we are saved.We should never rely on our feelings to tell us whether we are saved or not.
"Study to shew thyself approved unto God." 2 Timothy 2:15