What should she do as she prayed against herself asking that she not be successful and her du‘aa’ was accompanied by an oath?
Question

                I am a girl who offers the five prayers regularly and fears Allah, but I fell into the pit of the secret habit. I regret what I have done and I have repented more than once, but of two occasions I swore that if I did it again that my dream of getting good grades in my exams – which is my life’s dream – should not come true. This was so that I would stop what I was doing. But unfortunately I did it again. But now I have repented sincerely and my exams are in a few days’ time, and I am afraid that what I prayed for may come true. I wanted to fast for three days but I did not have the strength to do that because of the exams and psychological pressure. But I have decided to fast after I finish the exams.

My question is: is it possible for what I prayed for to come true?
Praise be to Allah.
    Firstly:

     The secret habit is an abhorrent and haraam action on the 
    part of both males and females. We have discussed the ruling on that and how 
    to deal with it in the answers to questions no.
    329 and
    101539. 

    Secondly: 

    What you have done of praying against yourself and asking 
    that you not be helped to succeed in obtaining high grades is something that 
    was not appropriate, because it was praying for something bad for oneself. 
    Falling behind in your studies is not a good thing; rather it would lead to 
    serious negative consequences. The Prophet (blessings and peace of Allah be 
    upon him) forbade the Muslim to pray against himself. It was narrated that 
    Umm Salamah said: The Messenger of Allah (blessings and peace of Allah be 
    upon him) said: “Do not pray against yourselves except for good things, for 
    the angels says ameen to whatever you say.”

    Narrated by Muslim, 920 

    Muslim also narrated (3014) from Jaabir (may Allah be pleased 
    with him) that the Prophet (blessings and peace of Allah be upon him) said: 
    “Do not pray against yourselves, do not pray against your children, and do 
    not pray against your wealth, lest that coincide with an hour when Allah is 
    asked for something and He responds to you.” 

    Thirdly: 

    If a person swears to do an act of disobedience then he does 
    it, what he is required to do is offer expiation for the oath he swore. This 
    expiation is not expiation for the sin he committed; rather it is expiation 
    for the oath that he swore. As for the sin, what he has to do is repent 
    sincerely from it. Part of his repentance is regretting what he did in the 
    past and resolving not to do it again. 

    See the answer to question no.
    103424 

    Thus, if a person swears against himself with the aim of 
    encouraging himself to do something or preventing himself from doing 
    something, as appears to be the case in your question, then it comes under 
    the ruling on oaths, and if he broke it then he must offer expiation for 
    it. 

    Shaykh Khaalid al-Mushayqih (may Allah preserve him) was 
    asked: 

    What is the ruling on one who says, “Insha Allah I should die 
    if I do such and such?” or he said “May such and such befall me if I do this 
    thing?” when he knows that he wants to go back to it and he said that in a 
    moment of anger? Is this regarded as being the same as an oath? May Allah 
    reward you with good. 

    He replied: 

    Firstly, it is forbidden for a person to pray against 
    himself… 

    Secondly, if a person prayed against himself in this manner, 
    intending to encourage himself to do something or prevent himself from doing 
    something, or to confirm something or to say that something was a lie, then 
    the oath was broken, then he must offer expiation for breaking an oath 
    (kafaarat yameen). For example, if he said, “If I do not go, may I fall ill 
    or die,” then he did not go. In that case he has to offer expiation for 
    breaking an oath.

    End quote from Fataawa ash-Shaykh, 2/145. 

    And Allah knows best.