Saturday`s run

On Friday I took the day off as I left work late and was pretty tired, so I bagged the day. But I am satisfied with 5 runs per week these days as I am working a lot. I ll have to do some kind of a workout, because all I am doing is running easy and throwing some strides here and there, but those workouts don't move the needle.
I ran with my brother yesterday at 11:00 am. and We ran in the blasco park very easy, We did 8 laps there, However, after the 6 laps , in the last mile or so I sped up the pace since I was feeling very flat even though I was running that slow. The increase in pace really got me activated and felt much better at the end. The effort was somewhat high, but the pace not that much, I wonder, How I could maintain that pace for 10k (it was around 10k effort), but with a lot of heat. Did the last lap in 4:05 (4:30-4:33 per km), the effort was good, but I have to move the body in the mechanic. Anyway, I have to find a way to get in some sort of a workout, so I don't lose my fitness as I adapt to the stresses of work.