It's exhausting being someone I'm not. How do I help myself keep going when this is the only choice I have at the moment? How do I keep reality from striking and giving me depressing thoughts?

Whatever the issue it, unfortunately it sounds really tough. No one likes to be in a place where they know there is a better answer or situation. As they say things change with time, and unfortunately that is true. Whatever it is now you need to try and be strong. Please never beat yourself up mentally or blame yourself for the way things are. Practicing breathing techniques when you're stressed will help you call yourself. Doing any activity you enjoy will help you to stay positive. If you can surround yourself with people who love you unconditionally. Please stay positive, even if it feels like you can't. Things will get better even though it may sound unbelievable.