Hello Canuk:
I would like to preface the following by expressing my admiration for the earnestness and simplicity of heart wherewith you have candidly and humbly described your predicament. The very fact that you recognize that this is a very perilous situation is a great grace indeed, for the vast majority of worldings are given over to sinful habits that transgress the 6th and 9th Commandments and they do not seem to care (or, be conscious of their grave state at all).
This is a chastisement that God allows in the inscrutable designs of His Providence, which is as infinitely and eternally clement as it is just: for those who reject actual graces and ignore the natural remorse of conscience have willingly bereft themselves of those efficacious graces that would have enabled them to persevere in the observance of holy chastity. Such a thing is also permitted by God in order to show His servants who are struggling with such habits what spiritual blindness awaits them if they do not do their best to fight temptation.
God does not owe it to Himself to give hardened and impenitent sinners the efficacious graces that can be obtained only by the humble and penitent prayers of souls who earnestly seek to rid themselves of all that is evil and sinful in themselves.
Very good advice has been given to you in this thread. I will add some of my own.
Most of the times, souls such as yourself are counseled to meditate on the Last Four Things, on the chastisements of Hell, of the horrible consequences of impurity in the natural and supernatural order, etc.. It is also salutary for you to reflect on the happiness of Heaven, the glories of divine grace, and the excellence of holy purity.
This is one of the reasons why devotion to the Blessed Virgin Mary is very efficacious against impure habits: because, if one perseveres in humbly serving her with filial trust, one will be led to consider the glories of grace which she shews in her most venerable person, the masterpiece of the Most Holy Trinity; the fruitful and supernal virginity that she has as a perpetual privilege and glory, which in turn leads Christian souls to the rehabilitation of holy purity by virtue of her office as Mediatress of all graces and co-Redemptress.
Furthermore, I would like to remind you that God has special care for those souls who are struggling against impure habits, and He always awaits them with open arms whensoever they return to Him by penance, as the Prodigal Son was welcomed by the father in the beautiful parable recorded in the Gospel according to St. Luke.
The worst thing you can do is despair. Don't give up. As long as you can pray, there is hope, no matter how much you may have co-inquinated your soul and body. For even to say the Angelical Salutation or invoke the sacred Names of Jesus and Mary is a grace that countless souls will never have, because they willingly choose to turn away from their last end, God: Who alone can fill the immense depth of the human soul, which was created to possess an infinite and eternal Good in beatific felicity.
Remember, that Our Lord compassionately forgave St. Mary Magdalene and gave her such grace as to persevere with the Blessed Virgin during His Passion, and at the foot of the Cross. He rewarded her humble penitence by making her the first recorded witness of His triumphant Resurrection, in preference to St. Peter and even the virginal St. John who had also persevered with Mary at the foot of the Cross. This He did in order to encourage penitents to strive for the cultivation of the interior life, even though virginal innocence has been lost. What has been lost in human nature can be gained and transfigured in divine grace, so that a penitent may again be pure and unspotted in the sight of the Heavenly Father.
Often meditate on the Passion of Our Lord, especially the Second Sorrowful Mystery, wherein one ought to reflect upon the horror and terror that afflicted the Sacred Heart at the sight of so much impurity that would be committed despite His saving graces more than the scourges that had shorn Him of His sacred flesh so that he was almost like a bloody skeleton, collapsed in a pool of His own Blood and shreds of sacred flesh. Offer to the Heavenly Father the humiliations and vexations that unsought-for temptations and involuntary movements of concupiscence cause you, and unite them to the affliction of the Sacred Heart during the Flagellation, and you shall thus make an oblation well-pleasing before God, and will assure you necessary graces.
The rush of adrenaline that suddenly terrifies your heart at the moment of temptation and the urge to gratify the caprice of the flesh passes most of the times in some minutes, if you have recourse to prayer and distract yourself in a wholesome manner. Pleasures last for seconds and are limited, but the love that Jesus and Mary have for you is eternal and infinite (which is why the sinner who rejects such love is justly punished with eternal Hell).
Again, have recourse to Mary Most Holy. Attached is a Litany to Our Lady of Perpetual Help that may be useful, since it prays for the graces necessary to overcome evil habits.
Please be assured of my prayers.