I doubt you can really do "too much" void meditation, but you should think about mixing it up with imagining bright sunlight around you and affirming that you are healthy. That might help warm you up and prevent this from happening. I know that whenever I'm cold, it's because I'm either stressed out, or on the opposite end of the spectrum and on the verge of sleep.
@Isaac, ask you direct questions about what? What does that have to do with this post?