probably not, its winter, you're probably a bit skint after christmas, things are boring at the moment, usally are at this time of year.
if you cant drag yourself out of bed or get dressed.
if you cant get to work or shopping or meeting friends
if you're house is smelly and dirty
if you're not eating or looking after yourself at all that is depression, if these things apply to you, get some medical help as soon as possible.
Agree with other posts, think its just the time of year, its dark when we go to work and dark when we come home, dont worry from someone who could quite happily hibernate each winter I think it will pass as the days brighten up. We've all been charging around for weeks too in the holiday build up, just your body's way of saying it needs to recharge. Spoil yourself.