Difficulties in Maintaining Holiness

I struggle with keeping the covenant (of circumcision), and sometimes when I violate the covenant, moments later something happens that upsets me. For example, today I discovered that I was not accepted for a certain job and I knew that I would be tested right now and I simply did not stand up to it. I am really upset about this but they say that everything that the Holy One, blessed be He, does is for my benefit. So how do I know when the Holy One, blessed be He, is acting for my benefit and when He is punishing me for my sins? The thought that things could be better but it is not happening because I do not resist my temptations lowers my mood and reduces my motivation leaving me with no strengthen at all. What do I do in such a situation, Rabbi?

Hello,
Everything that the Almighty does is for the best.
Even punishment for sin is for the best because it cleanses us and brings us back to the Almighty.
It is important to remember that although sin is very serious, every moment of overcoming the prohibition is an immense merit, unparalleled.
Therefore, a person who overcomes for an hour not to sin, and again and again distracts and overcomes, and at the end of the hour fails, has dozens, maybe hundreds of overcomings, and only one sin!
The thought that every moment of overcoming counts on its own, and at the end of the day, if you fought, you have much more merits than sins, gives the desire to overcome another moment and another.
And ultimately, you will succeed in overcoming completely.
It is very important to pay attention to another thing: overcoming the evil inclination cannot come at the last moment, after a person has allowed themselves to see forbidden things or think about forbidden things, because then the evil inclination is already stronger than us.
The only way is to stay away from the sources of desire and the evil inclination. This way, the evil inclination is still small, and it can be overcome.
Wishing you great success.

Shulchan Aruch, Even HaEzer, Siman 23