Marathon (Training) Motivation or Lack Thereof

Marathon training motivation or lack thereof has been a problem for me these past couple of weeks.  Do I really have to run all those miles? Why did I sign up for the marathon?  It's so hot?  I don't feel like it, etc.   The 2018 Chicago Marathon is now 18 weeks away (or thereabouts) and it is time to put up or shut up. 

I've been running fairly consistently for the past year so I should be ready to tackle marathon training from a physical standpoint.  It's the mental side of it that I have been struggling with but I'm not sure why.  Is this just a normal pre marathon lull?  Am I bothered that I don't have a clear set of marathon training buddies?  Do I just have too much else on my mind? 

I guess none of that matters, I just need to get out there. 

Do you struggle with training for big races?  What do you do to get over the mental hurdles? 

The 2016 Chicago Marathon. 
It looks fun????