Maybe you need to mix it up, most training plans do a 80% of long slower runs to build distance, with an interval faster short run and a hill work run. I took out cheap runners world subscription for 6mths it’s been quite useful with bits n bobs of advice.
Did a slog 5k tonight didn’t want to do it, dragged myself out when DH got home and then my music stopped after a km ggrrrr flipping slog but did it 
Running 503k! 