i've had the same thoughts and feelings you've experienced. Its hard especially at such a young age and you want to believe in God and do the right things, but things happen and you may slip and make a mistake. I've been trying to come to grips with my anxiety and beliefs also. Reading the Bible daily, attending services and praying usually keeps me grounded in faith, but of course once the anxiety sets in my head gets the spinning. I say the best thing we can do is pray for guidance daily, ask for forgiveness and also if you have therapist talk to them also.