Space station core unbalanced

[Saqu0007]

So I launched a space station core in orbit around Kerbin. It's made up of (from top to bottom) a Cuppola module with 4 high gain antennae,  a hitchhiker with 4 docking ports mounted around it, a service bay holding batteries, a RSC fuel tank, a Liquid-Oxidizer fuel tank with RCS controllers and 8 OX-4L around it and a poodle engine at the end. I had no problem getting it into space and achieving a stable orbit have since had it docked with with a laboratory, lander I needed to refuel before sending to Mun, and another fuel tanker I sent up to refuel the station. I'm planning on moving the think to a Munar orbit so dedocked the lab and started my burn only to find that after 3 - 5 seconds it started pitching and will spin uncontrollably if I don't turn the engine off. From what I can tell there's nothing that should be unbalancing it. I also tried filling the tank to full thinking maybe it's top heavy (it was at half tank), but that didn't do anything either. Is there something I'm missing? The only thing I can think is that it's unbalanced, but for the life of me I don't know how.

[Rocket In My Pocket]

We'd need a pic prolly to do any real troubleshooting.

However, I've moved off balance stuff before by reducing throttle and making sure SAS is at full strength. (Turn off caps lock mode.)

Slowly increase throttle until you find the tipping point, then back off and keep it there.

Edited March 7, 2019 by Rocket In My Pocket

[Ozymandias_the_Goat]

The center of mass is clearly not lined up with the center of thrust. Certainly, @Rocket In My Pocket poses a viable suggestion, however, also consider a mild redesign of the station to include a docking port on the bottom. Then, dock with that port, and your balance issue will be solved.

[Espatie]

And/or attach the biggest reaction wheels you can find to it.

[Vanamonde]

Does it spin with the engine off, too? If so, your joystick might not be centered and/or you might have accidentally applied some trim. 

Either way, the question has been moved to support.