1) don’t know how old you are, but being a teen, I know Hashem TOTALLY doesnt expect me to reach thst level so quickly! Hashem only expects stuff you can do, that type of emunah is pretty high. Everyone falls too, you are totally not expected to have unbreakable emunah in my opinion…
You have to work up to it, just explaining to yourself that Hashem is there, give him control…it takes time, patience, and lots of work!
2) As human beings we are granted the ability to feel. We are supposed to be upset at times, in normal circumstances where most people would. When someone dies you are supposed to be sad. But there is an up to a point type of thing. Just like with mourning a person that the torah has rules on. We were just talking about reactions in my phsycology class today. Part of accepting something has happened is feeling it, even if for a split second. You tell yourself, “okay ______ happened. So I feel _______. That is ok, it is normal. Calm down. Let yourself feel it, then tell yourself why you should let go of the feeling and how how to accept it. You then tell how hashem is really in charge
3) Again, time patience, and work. No magic pill, I am sorry.
*You just do, just let go, it happens sometimes that you cant anymore and then you just realize its HASHEM, and you give it all over.
* My friends recommend it, never was able to read mussar books