I'm a 22-year-old student who lives in Australia. I'm extremely sexually frustrated. I sometimes find it hard to control my urges. When I do give into my urges. I find that something always goes wrong in the day that follows; my friends also have the same problem. Why?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

It is Haram to get sexual pleasure (i.e. having sex, masturbation, flirting and so on) from any source except in marriage.
So, it is your duty to repent, regret and decide not to return again to misdeeds. Also, avoiding places of corruption, having good friends, remembering Allah and doing more optional deeds (and obligatory worship) help you to be on the straight path.
No doubt that disobedience causes frustration and anxiety. This is the unavoidable result of disobedience. One should know that genuine happiness lies in following the Divine teachings just as wretchedness results from disobedience.
Allah says: {Whoever works righteousness, whether male or female, while he (or she) is a true believer (of Islâmic Monotheism) verily, to him We will give a good life (in this world with respect, contentment and lawful provision), …….} [16:97]
Also, it is natural to be punished due to disobedience.
Allah says: {"But whosoever turns away from My Reminder (i.e. neither believes in this Qur'ân nor acts on its orders, etc.) verily, for him is a life of hardship,……}[20:124]
Then, only repentance, true resolution and good deeds may prevent the occurrence of distress. We pray Allah to relieve your sorrow and guide you to the right path.
Allah knows best.