I think we girls go through those types of feelings when we break up. I also had a three-year relationship in high school, and yes, when I broke up with him I had some similar feelings. So I can relate to what you're going through!
This is going to sound crazy, but here goes: I can't promise you'll meet a man who will love you as much as he did. I say that because I want you to embrace the right perspective when it comes to husbands and romance. God doesn't promise such things, nor should that be our focus in life. Christ should be our focus. All the rest—husbands included—are added to our lives as God sees fit for His purposes. Matthew 6:33 says, "Seek the kingdom of God above all else, and live righteously, and He will give you everything you need." Sometimes what we want and what we need are two very different things. That's why I'm so proud of you, sis. You chose what you know you need over what a part of you still wants very much. That, my friend, is true and wonderful faith. So don't be discouraged! Take heart, and rest in the Lord, knowing that He cares for you deeply!
That said (here comes a ray of sunshine), God blessed my socks off with a husband whose love for me utterly eclipses anything I had experienced before. I didn't realize how awesome it could be. He is wonderful, and there is no way I could EVER have met him until I learned to let go of less-than-godly relationships. I had to trust that God knew best. Easy to say, hard to do! C.S. Lewis penned some words that always humble me each time I read them:
"We are far too easily pleased, like an ignorant child who goes on making mud pies in a slum because he cannot imagine what is meant by an offer of a holiday at the sea."
I hope what I've written makes sense, sis. In a nutshell: what you're feeling is normal, it will take time to heal, Satan will be attacking during the process, and I am proud of you for making such a wise and godly decision! Hang in there; the best thing you can do is trust the Father who loves you DEARLY, embracing the fact that He will give you what you need when you need it.
So be at peace, sis—you made the right decision, one hundred percent, no question in my mind.