Hi Crystal - I'm very sorry, and I can totally relate. My father was diagnosed with terminal esophagus/stomach cancer about 2 months ago. They thought they could operate, but once they went in, it was too far spread. They are also giving him 4-8 months. I have 1 brother, but like you have really no extended family. I live about 7 states away from him (I moved from CA to NE right before he was diagnosed) and know what it's like to try and be the strong one for everyone.
I really don't know what to tell you as far as how to deal, I'm more so writing because I'm in the same boat. There are huge fluctuations in emotions and I have to put on this professional face for my job, put on a 'strong' face with my mom and brother when all I want to do is cry. I guess I just wanted you to know that you're not alone. I too am searching for some sort of advice or support. At 27 yrs old, you never expect to bury your father, especially since I can't be there during his last days. I'm less concerned about my feelings, more so how do I deal with his anger and depression during these next few painful months. I want him to be at peace before he goes, not angry at the world.
Anyway, I'm sorry I can't offer more advice; I'm new to this too. I just wanted you to know that you're not alone in your pain. It's a crushing experience and I totally understand. Please feel free to send me a message anytime. Hang in there...