It's quite common to "fall in love" with your T, as you'll find out from others too. I'm not sure why your T is telling you that he's in a relationship because whether he is or not, it's unethical for him to have a relationship with you outside of therapy. Maybe he thinks that was relevant to the issues you were discussing? If he was attracted to you, that's something he needs to keep from interfering with your therapy. Could it be that you are assuming things about him? You also say that you don't think he wants to see you anymore. Plus, you have unresolved issues to discuss with him, still.

I would suggest going back and first, bringing up what you posted here. Unless he is really inexperienced, he should tell you that it's normal to have strong feelings for a T, and he may tell you about transference. It may be hard since you're about the same age, but it's a T's job to hear this kind of stuff, and it's what you're paying him for. If you're too embarassed to tell him, can you email, or write it out and give him the paper?

If it's affecting your sleep and your relationship, I think it's important to go back. Alternatively, you could see someone else, maybe someone older, or a woman instead? But that doesn't guarantee that you won't develop strong feelings for that T, either. It's not wrong to feel attached to your T; in fact, it's an important aspect of therapy. If you discuss it with your T, it can be very productive!

Good luck!