Don’t expect yourself to be cured of anxiety in one day, healing takes time but it’s definitely worth it. 

The best way to manage is by going out your comfort zone gradually but consistently. You’ll feel like garbage at first, but once you deal with whatever was making you anxious, you realize it’s nowhere near as bad as before.

Things like cleaning your room, doing your homework, running a small errand, or even just climbing out of bed early.

You’re intrusive thoughts will lessen with time, you’ll feel hopeful and optimistic again, sleep will be better, it just takes time.

Remember though, anxiety will never go away fully, if it did you’d be considered a psychopath. It’ll still be there, but only when you’re in actual danger.

And in case you need to hear this: 
You can’t go crazy through anxiety.
Panic attacks aren’t permanent.
Your negative thinking is from anxiety, not who you are.
Intrusive thoughts are completely normal and they don’t define you.
Anxiety shows you the worst case scenario, not the most logical.

Hope this helps!