No, you haven't been deceiving yourself but the devil certainly will try to deceive you into thinking you have been. One of his oldest tricks is to try to get new believers to doubt their salvation to doubt that God has really forgiven them, and that they are now part of His family forever.
But don't listen to him! If you honestly opened your life to Christ as best you knew how, and you sincerely committed your life to Him, then your sins have been forgiven and God has made you His child forever. Jesus' promise is for you: "I tell you the truth, he who believes has everlasting life" (John 6:47). The Bible also says, "Yet to all who received him, to those who believed in his name, he gave the right to become children of God" (John 1:12).
In other words, trust God's Word, and not your emotions! Emotions have their place; God gave them to us, and they can bring us great joy (as well as sorrow). But emotions come and go, and they are not a reliable gauge of our standing with God. The night I came to Christ in an evangelistic meeting I felt very little emotion. But down inside I knew something was different, and in time I learned to trust God's Word, and not my emotions.
Thank God for sending His Son into the world to die for you. Then make it your goal to grow closer to Him through prayer, the Bible and the fellowship of a church where Christ is preached.