Okay, a little introduction about me and my mental health. Since the age 12, I had always had an obsessional worry that sometimes produces unwanted thoughts, mental images and feelings for example at the age 12 I had unwanted thoughts about God & Jesus to the point not wanted to pray, see images or go to church without triggering a disgusting thought. Then, later on, I start worrying about committing the unpardonable sins. (I still think about once in a while) somewhere either on mid-2014 or 2015 I overcame the unwanted thoughts and feelings relating to Jesus and god and then I developed a fear of being about a pedophile too the point I stop interacting or barely interacted with family members that had young children and hated going to areas that had children nearby even as far as not watching movies that contain children. Which in turn affected my social skills. I overcame the fear of being a pedophile in late 2017 along with few others. Now my anxiety is 10x times worse than before to point it's sometimes plain stupid like fear of food and yellow or worrying about having early onset Alzheimer's even tho I am 17 years old and many many more that come and goes even the fears I had overcome. As of now, I am highly hypervigilant of what I say, do think, behave, and my thought process and feelings. My main fear is being a sociopath but my obsessional fears go back and forth in a matter of minutes, hours or days.
The pedophile thought is because your a teen with hormones gone wild. You know that's a wrong direction to go, your afraid of it, and so you give it power. The impure thoughts preventing being near God are on the same lines. It's like saying "Don't think about.....whatever" you're naturally going to think about that. That is human behavior. So being anxious about your anxiety is actually making it worse.
Being a teen isn't easy. I once heard a young teen scream to her mom , "I'm so awkward!!" while in public. I thought she was just a pretty kid, did not appear awkward at all. Lol however unfortunately that's the norm and I was the same way.
I would do some serious meditation and praying. Meditate first so you can pray!! Focus on your breathing. The thoughts will come, let them pass. Don't try to "control" it. Let it be.. And continue to focus on your breathing. You can also do Christian meditation and breathe in and out the word of God. Remember the thoughts are not the sin, but rather believing the thoughts and not telling them no is. Even Jesus was tempted with Satan in his thoughts. But he used the word of God to dismiss it.
FYI I've had similar "thoughts" but I don't dwell on them and let them just pass, dismissing as silly, ridiculous, etc. We always have the power to say no to a sin. Demons enjoy messing with us. There's no need to fear though, trust in God instead.