God often protects His children from the strange woman before it becomes the permanent commitment of marriage..
One thing you can do is to commit it to the Lord as often as she comes to mind, pray, and stay in His Word. If you don't have a 2-3X day bible reading routine, that will help a lot. Don't waste this suffering. Use it to propel you closer to the Lord. If you aren't 100% certain that you are going to heaven, please watch this video.
How to Become 100%
Lastly, learn from your mistakes with this one. You don't want to go through this again. Careful to follow the Proverbs advice.
Avoid sluts like they have AIDS.
Set the standards against physical relations before marriage. I was the one that said No to premarital contact in past relationships. You can't trust the flesh or that of the woman. Only date those who are on the same page (sincerely) about the topic in the link.
One more thing, when thoughts of her come to mind, tell your brain NO ! and make it be under submission to God's Word that you keep in your pocket to memorize through the day. Avoid any female relationships for a good while..
If you need self discipline to establish those, I recommend a good martial art class to help you accomplish those goals by integration of stress busting physical activity. FMA Filipino Martial Arts are usually good about leaving out the weird Eastern religions. I developed my own Combat system, but am in WV.