@Gabe0511 First practical thing: You need an STI screen. Most prostitutes are regularly tested, but best not leave these things to chance, even if you used a condom. In the UK there has been a rise in all STIs: warts, herpes, 'super'-gonorrhoea, syphilis and HIV - so you owe it to yourself to ensure that you are not infected for the things that can be tested.
Your choice was to succumb to your sexual lust and pay for sex with a prostitute. That is done. Finished. History. You now need to move on ... Galatians 5:16-17 What I say is this: let the Spirit direct your lives, and you will not satisfy the desires of the human nature. For what our human nature wants is opposed to what the Spirit wants, and what the Spirit wants is opposed to what our human nature wants. These two are enemies, and this means that you cannot do what you want to do.
Second practical thing: As you say you are a Christian, your 'guilt' is probably because you know the above, but then you will also know that forgiveness will be given if you prayerfully truly repent.
Moving forward, my advice would be to seek the counsel of a Christian who is mature in-Christ to help you with being accountable and to support your prayer-life. If you feel your OCD is affecting your mental health then a medical doctor may be able to help, alongside your own crying out to the Lord, in prayer.
Final thing: You will also need to be honest with the woman who you want to be your wife as a Christian marriage must be built on openness and honesty.
I wish you well in your struggle with 'things of the flesh' and, hopefully, a new determination to walk in the Spirit. Romans 8:1: There is therefore now no condemnation for those who are in Christ Jesus, who walk not after the flesh, but after the Spirit.