Amateur God needing help T_T

I have this idea of an awesome vampire story that already has a juicy mechanic and overarching storyline, but I can't get started on it at all because I'm stuck with the setting >_<

You see, I want to create a world where there is no such thing as a sun or sunlight.

I've gone through tons of ideas to no avail.. starting from disregarding everything and treating it as a magical world where the conditions are suitable for life to exist even without a life-giving celestial body (since everything would freeze without the warmth of the sun, not to mention the lack of oxygen thanks to zero photosynthesis, which relies on primarily sun power)

Then I moved to a super outlandish idea that 'solved' the problem with the existence of oxygen by putting a huge ass ancient electrolysis machine at the bottom of that world's ocean (believe me, the super crazy back story I created surprisingly makes sense *_* I don't wanna spoil it yet though). This also allowed the fauna of that world's ocean to be really unique - most of them would evolved to cooperate electricity in their bodies, like eels do in our world~ and it also makes the oceans of that world extra dangerous thanks to them being electrically charged *O*

With oxygen solved, I realized that the world would still be colder than a freezer, even with oxygen.. and this is one of my biggest problems thus far. Our main source of heat is from the sun, and without a sun, (or even far enough away from a star) a planet would be freezing to human standards. I toyed with the idea that the heat comes from the ground itself, where the planet has a lot more tectonic and volcanic activity.. but I doubt that'd be enough, really T_T This is where I could use the most help.

Of course, without a sun anywhere near the planet, it would be unbelievably dark. So what I came up was to have auroras periodically streaming across the sky, providing an eerie lighting for the setting. Auroras are usually caused by the collision of charged particles directed by the Earth's magnetic field, which would seem like it makes sense to have them on my world since the there would be some funky magnetic fieldwork thanks to the electronic bzzt bzzt of the world's oceans.

Another aspect that relies on the sun is the planet's orbit, which usually circles around the sun thanks to it being pulled by the sun's gravity. A planet without a sun would then spiral out of control and float freely in outer space. While this might sound like the Death Star, that thing is a freaking spaceship and has its own propulsion system. A planet without an orbit would more likely crash into something than float happily around in space.

How I solved this was to come up with yet another crazy idea; I put the planet between three black holes. While black holes compress everything into their center, being in between three black holes allows the planet to spin around almost indefinitely in the center where their gravitational pull intercepts. Whenever the planet almost gets sucked into one black hole's gravitational field, the opposing two black holes pull it free and the cycle repeats ad nauseam.(By the way, being 'close' to a black hole isn't close at all - the planet is lightyears away from each of the three black holes - even further than our solar system's width @o@)

And.. yeah, that's about it. My attempt to make a working planetary system with my very very very very limited knowledge of astrophysics and ecology :P Hopefully someone would come up and point up what I'm doing wrong, as I really want to get this right XP The idea is so awesome, but I need more knowledge to make it work T_T;