Christina, life is like the wavelength with its highs and lows. Sometimes you have extended sleep sessions because your body wants to rest and repair. I have a friend who started smoking and nicotine was accelerating the brain activity but at night, once he was off to sleep, he could not wake up after seven or eight hours of sleep and was sleeping excessively. Even if he managed to woke up, he'd feel tired unless he smoked a cigarette or two... I went off-topic here but what I mean is that sometimes the body really needs to rest... If it is happening more often and frequently, then it is worth looking for the cause. Else I'd suggest to stay relaxed and not to worry.
Hope you are feeling better now.