6 weeks to the Year End marathon

At the 42km and 150 m mark, 25 m to go

I am facing the ultimate runner's dilemma, to run and finish a goal I set out at the beginning of this year which is to run 2 marathons, (so far 1 finished 1 half marathon in August) and risk injury ranging from patella (knee) problems, Iliiontibial band problems and possibly even overexertion, or I may just pull it off with little damage to my body.

To quit at this stage is another option whereby I listen to my body which is screaming, 'No more' and take that rest which many many of my friends have stopped maybe a decade ago, ie. to switch to a gentler sport like swimming or cycling.
On Tuesday, I ran 10km and it was not really fun, although I enjoy the breeze and scenery at the East Coast Park, the reality sets in maybe 3 hours after the run when I am tired and the endorphine and adrenalin have all subsided and the 'good feeling' generated from these natural body chemicals dies out.

Should I run or should I stop ?