Jon...

Sorry to hear you are so frustrated. Have you been measuring? My husband has been lifting weights 3 times a week and hasn't lost a pound since he started in January. The good news is that we measured this morning (I can see that he's getting smaller, even if the scale doesn't say so...scales lie) and he's lost 7 inches, mostly from his stomach and hips. If you have equal volumes of muscle and fat, the muscle does weigh more. If you have equal weights of muscle and fat, the fat will take up more space.
It's possible that the quiche may be responsible, especially if you are one of those people who are sensitive to eggs or dairy. OTOH, it may not be.
Congrats on not letting your frustration lead you to a carb binge. That kind of self-discipline will pay dividends if you stick with it.