If you have repented for your sins, as The Bible says to do in Luke 13:3, and acknowledged that Jesus is the Son of God (John 14:6, 1Tim.2:5, John 6:27,33,  John 3:36, 1John 5:12, John 10:30, John 8:58, Heb 1:2, 1 Cor.15:3-4) and asked Him into your life, then you are saved. If you have done Rom. 10:9 -10, then you can have the assurance that you are saved. It is not by our works, or by being good that gets us saved. We can never be "good enough" to earn our salvation and gain Heaven (Tit.3:5, Eph.2:8-9). We all are sinners (Rom.3:23, Rom.3:10).   Salvation  is a free gift (John 3:16).   We can all have God's full assurance of our salvation (1John 3:19, Heb 6:11-12, Heb.10:22, 1Thes.1:5, Col.2:2, Acts 17:31, 2 Tim 3:14.)

The fact that you feel bad when you sin is strong evidence you are saved. If you repent each time and ask God to help you to stop, then He will help you. The fact that you still have these desires does not mean you are not saved. You simply need to grow in the things of God. The number one way is to renew your mind by reading the Word of God.   It is also very important to pray, attend a strong  Bible-teaching Church, fellowship with committed Christians, and stay away from those who do not know Him and practice sin (Pr.3:7, Ps.1:1-6).   You need only to confess your sin's before God. If we confess our sins, He is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness (1John 1:9).

We all need God's help each day to live right. Rom.4:7 say's, "Blessed are they whose iniquities are forgiven, whose sins are covered." We all need to stay in His Word, read it every day and grow stronger. It then gets much easier to stay out of sin. It actually should come to repulse us, that we learn to hate sin (Pr.8:13, Ps.119:104). 

As far as your past, the Bible say's in Phil.3:13-14, "Forgetting those things that are behind, and reaching forth unto those things that are before, I press towards the mark for the prize of the high calling of God in Christ Jesus." Don't be discouraged, but get into the Word, and you will see, you will grow strong in your faith and have confidence in His Word.  Romans 10:17 says that faith comes by HEARING and hearing the Word of God.  I would encourage you to read the Bible out loud each day so God's Word goes into your ears.  The more senses you engage, the better.  (Prov. 4:20-23)