PSA 139:1 O LORD, you have examined my heart and know everything about me.
2 You know when I sit down or stand up. You know my every thought when far away.
3 You chart the path ahead of me and tell me where to stop and rest. Every moment you know where I am.
4 You know what I am going to say even before I say it, LORD.
..6 Such knowledge is too wonderful for me, too great for me to know!
7 I can never escape from your spirit! I can never get away from your presence!
8 If I go up to heaven, you are there; if I go down to the place of the dead, you are there.
9 If I ride the wings of the morning, if I dwell by the farthest oceans,
10 even there your hand will guide me, and your strength will support me.
11 I could ask the darkness to hide me and the light around me to become night -
12 but even in darkness I cannot hide from you. To you the night shines as bright as day. Darkness and light are both alike to you.
13 You made all the delicate, inner parts of my body and knit me together in my mother's womb.
14 Thank you for making me so wonderfully complex! Your workmanship is marvelous - and how well I know it.
15 You watched me as I was being formed in utter seclusion, as I was woven together in the dark of the womb.
16 You saw me before I was born. Every day of my life was recorded in your book. Every moment was laid out before a single day had passed.
17 How precious are your thoughts about me, O God! They are innumerable!
18 I can't even count them; they outnumber the grains of sand! And when I wake up in the morning, you are still with me!
PSA 37:23 If the LORD delights in a man's way, he makes his steps firm;
24 though he stumble, he will not fall, for the LORD upholds him with his hand.
ISA 49:14 Yet Jerusalem says, "The LORD has deserted us; the Lord has forgotten us." 15 "Never! Can a mother forget her nursing child? Can she feel no love for a child she has borne? But even if that were possible, I would not forget you! 16 See, I have written your name on my hand.
ISA 40:26 Look up into the heavens. Who created all the stars? He brings them out one after another, calling each by its name. And he counts them to see that none are lost or have strayed away.
27 O Israel, how can you say the LORD does not see your troubles? How can you say God refuses to hear your case?
28 Have you never heard or understood? Don't you know that the LORD is the everlasting God, the Creator of all the earth? He never grows faint or weary. No one can measure the depths of his understanding.
29 He gives power to those who are tired and worn out; he offers strength to the weak.
30 Even youths will become exhausted, and young men will give up.
31 But those who wait on the LORD will find new strength. They will fly high on wings like eagles. They will run and not grow weary. They will walk and not faint.
PSA 147:11 the LORD delights in those who fear him, who put their hope in his unfailing love.
Just a bit of advice for the future:
Many Christians question their faith at some point. Teenage years sounds like the right time. I went through that too. Did you? If you didn't, you might later on, don't be surprised then, just humbly bring all your questions to God and pour out your soul to Him and seek Him. Faith comes from hearing. Hearing what? The Word of God. One has to study, and pray (even if they don't believe that much) and it will end up well (if one has a desire for God and for righteousness).
Of course, praying is the number one thing to do. And when you get to talk to him again, if he has questions, only answer them honestly, from your heart. I know some Christians give superficial traditional answers to the inquirer, which don't help a bit. I think that saying: I don't know, is a much better answer than a superficial one, the one nobody really believes anyways. At least the person then knows that he is not the only person out there with such questions and with no answers...
And please, just remember to put God ALWAYS first in your life, before that other person. Do what GOD wants you to do, not what your "feelings" tell you to do. It's very dangerous for anyone to become dependent on a person instead of on God. God will have to teach you then to rely only on Him. Because your soul needs to learn to rely only on God...
Just remember, what you are going through is something that GOD WANTS you to go through. It was written (in his "book"), your path was made before you were born. God's purpose in our life - is to make us presentable and worthy to enter the kingdom. And everything else is number 2. So whatever God does, it's for making you stronger and better in your walk with God. That's what counts for eternity. Everything else is very temporarly and will pass away. Seek ye FIRST the kingdom of God. God is the source of my strength and my comfort forever. God doesn't want to be second in your life, He wants to be first (just always remember that).