Hi, this is my first time to brew a lager, so I'm still a little green behind the ears. Its a bohemian lager. I was using liquid wyeast, and started it 3 days before. After I brewed the wort I pitched the yeast at 75 dF and put it in the fridge at 50 degrees. My fridge has been fluctuating in temp a lot, from 43-57, and its the 4th day since brewing, and there is no head on top of my beer( i know that lager yeast brews on bottom so there might not be any) and no bubbles coming from the airlock. Is my yeast stalled, or is this normal? thanks!