Is the act of baptism because of not wanting to go to hell the result of repentance? I can't say that I had a strong desire to live godly before my baptism, but at the same time I can't say that I was planning on continuing to sin or do evil things. I know that I was afraid of going to hell and the idea of continuing to sin and the like did not enter my mind, as I wanted to do what I thought I knew I had to do.
Shortly after being baptized I seemed to have no interest in personal Bible study and going to church. I had a hard time appreciating the sacrifice of Jesus during the Lord's Supper. I was struggling to feel the emotion that the older Christians around me seemed to convey. I understand that, just because I struggled with these things after being baptized, my baptism isn't nullified.
I guess the big doubt in my mind is if I really felt convicted about whatever sins I committed to need to obey the gospel. I cannot specifically remember what my thoughts were toward my actions, only that I needed to obey the gospel to not die lost. I felt so relieved after being baptized, but I do not know why I had no desire to study God's word more and stay vigilant at school. It wasn't until I hit puberty that I really understood the depth of my sins, and that was a year ago; yet, I had no doubts about my baptism even then.
I don't know the cause of my doubts right now.
My guess is that you expected that your feelings would stay the same or become stronger; yet, feelings are unstable (Proverbs 28:26). Christians don't worship and study because they are pushed into doing these things. They do it because they know it is the right thing to do. In the process of doing those things, their faith grows and the Word of God becomes a part of who they are. "Do not let kindness and truth leave you; bind them around your neck, write them on the tablet of your heart. So you will find favor and good repute In the sight of God and man. Trust in the LORD with all your heart and do not lean on your own understanding. In all your ways acknowledge Him, and He will make your paths straight" (Proverbs 3:3-6).
The problem is not your baptism in the past, but your need to grow. You know you are not where you should be, so put the effort in. "Therefore, putting aside all malice and all deceit and hypocrisy and envy and all slander, like newborn babies, long for the pure milk of the word, so that by it you may grow in respect to salvation, if you have tasted the kindness of the Lord" (I Peter 2:1-3).