"Be still" obviously means stay calm.
"the belly of the beast" likely refers to a person's lowest point in their life.
"limits be unknown" means keep pushing, ignore what others say.
"efforts be your own...Don't break character"- authenticity.
"Is this real...?" it will have felt like a dream when it is over.
"Rise up like the sun and labor" probably means to stick to your routine, keep going, and not stop, work hard each day.
"Was there something out there for me?"- you're not alone but between the two of us, you'll succeed first.
The second half of the song keeps reiterating to keep pushing through anything life throws at you. A good song for people who feel hopeless.