PS...
At your age, I really hated being reminded of how young I was... but really, there is some wisdom and some ability to cope with life and change that comes with age. That's what I'm learning. When I left home, I had a group of very close friends who were my whole entire world to me then. (And I'd never had a T at that point). I thought my heart would crack in half if I lost touch with them. And I did miss them, and wish they were around. I have had, and continue to have many lonely times... but as I've had more and more losses and deaths and separations in my life, I've learned that my life does go on. My life will have highs and lows, and richness, and love, and attachment, and loss... forever. I've lost a lot of friends, though I carry their memories in my heart and they're always a part of me.
I've noticed as I've talked with people older than me (I'm still very young, too- only 25)... that they have even more peace and perspective with this. It WILL come in time.
Maybe some of us forget how different, and how much bigger, loss seemed to us when we were younger. I know some of the responses here haven't been very understanding and sympathetic. But I think your feelings about T are a normal part of the process, and reflect your healthy ability to attach. It will serve you well through your life, especially as you learn to balance it with letting go. It's important to have both in your life.
Your feelings are ok. It's ok to be where you're at right now. I hope T can support you through this.
Sorry to ramble on...