I feel crazy because I'm 19 as well and I swore I thought I was the only one at this age dealing with anxiety. I knew it wasn't true but I haven't met anyone at my age with this issue so far. Actually I've been dealing with it since the 8th grade. I'm a christian too and everyone says to trust God and I very well know this. Sometimes I can start quoting scripture and other things while I'm becoming anxious and it helps, other times it doesn't seem to work. It is so hard because I feel like failure in my faith and a bunch of other lies I have ingrained in my brain over the years that I don't even realize are not true. I was reading in Lamentations the other day and it says "It is good for a man to bear the yoke while he is young" (3:27). It is somewhat comforting because as I have talked to adults, the older you get, the harder it is to break old habits and to learn from them. I still get mad because I hate that I have to even deal with this at all but then I hope that one day when i'm free I can help others at this age who don't even have access to this program or anyone supportive to even help them.
I admit it is so hard and frustrating, in fact i got in the depression slump a few months ago and i just didn't know what to do with myself. I hated myself for being such a "failure". But by the grace of God I came out of it. One thing that I find is really helpful, is to admit your emotions, and don't hate yourself for feeling them, they are emotions that God GAVE us. It is important to work them out because if you push them aside they will only add to your anxieties. I tell the Lord how I feel even if I think I shouldn't feel that way (not always, I still have a hard time), he already knows your every single thought and emotion he just wants you to tell him and ask him for help. Cry out to him.
Today I had to go to work and I didn't want to drive (I get really anxious and my thoughts start going a little crazy). I basically have to do this everyday and you would think I would have gotten use to it by now and over the thoughts but I haven't (although some days are way better than others). But I just felt like I couldn't do it, which made me sad, so I started crying in my car while I was driving to work, it was the only way to address my emotions without allowing the anxiousness to overtake me. I cried out to the Lord saying I want to be brave and strong but I couldn't do it (even though I was driving) but as soon as I said that last part, I thought of the scripture "I can do all things through Christ who strengthens me" Philippians 4:13 over and over and then I started reciting Psalm 23. I then thought to myself, i am brave, because even though I'm still getting anxious, I still am driving. I didn't decide not to, I still did it, even though I didn't feel like doing it, even if i took the least stressful route (the longest way). It doesn't matter, I was brave because I made a choice to go.
The important thing to remember is that the Lord sees your heart, he knows your intentions, even if you are freaking out still, he sees that you are trying to put healthy thoughts back into your life. Thoughts that are uplifting for the person he created you to be, not the person you once were. Now that you are a Christian he sees you holy and clean. Just confess to him that you know you are supposed to trust him, but you can't or don't want to, and ask him to help you to trust him and believe him. I have to do the same thing, he will change your mind and thought process, he is still changing mine.
Good luck, You CAN DO IT! Don't give up, you are stronger than you think or can even imagine. Actually everyone on here is, it just takes a little faith to believe this truth!

I will be praying for you