Tomorrow will mark the first Thanksgiving that I will not spend with my family. I feel completely dejected. I did not think it would be this hard for me, but if I'm feeling this bad now, I can't imagine how I will feel in the coming weeks. Does anyone have any tips on how I should cope with this? 

Do you have friends in reach? Sometimes friends make better family. I have one friend who always welcomes me, even when I am a bit of an idiot.  That is more than I can say for most of my family.

I agree with LordKat that you should try reaching out to some friends. No one should be alone for the holidays. In the meantime hugs.
Mariah

I like KAT's suggestion that sometimes friends are just as good or even better than family.

I also think there are times when enjoying your own company is a skill that comes in handy. You're an interesting, fun person. Get in touch with that part of yourself. What do you like doing with yourself? What sort of fun things could you do without other people around?

Once you figure this out, days you need to spend alone, even if they're holidays, you might even enjoy them more than if you were with others.

Good luck and hugs, Keira. I hope you have a wonderful day.