Lots of runners can feel the same way Graham.
Think about varying your routes
running route in reverse direction
running with mates
joining a club if you don't belong to one- you dont have to be a star to belong to a club
how about doing small interval session initially eg 5 x 3-4 mins/ 90sec jog then running steady half hour.
or doing a lap long run and at the end of each long section running a measured mile and see how fast it is eg 15 mins mile 15 mins etc
or
combining steady long run with form of circuit training
eg the Oregon circuit.
Devise route and at every appointed station stop and exercise eg press ups,crunchies etc.
Great for conditioning and endurance.
Above all use your imagination and be creative in your approach to training
And remember to have fun
Best
Bud