Work-outs getting harder

Sub-tempo + interval workout: 20 min w/up. 5 Strides. 12 min run @ 4:22. 3 min full recovery. 4 X 800 m at 5 km pace with 2min easy jog btwn. 10min c/d
800s: 3:07, 3:06, 3:03, 3:05.

When I got to the track I realized I do not remember what my recovery should be so I just went with 2min jog. Now I know it should have been 400m jog, but since I jogged really slowly it was approximately 200m, so it is ok.
Already during the sub-tempo I could not breath properly, as if my rib cage was tied together. Hm weird. That added to the hardness of the workout. But that had nothing to do with the fact that my legs were getting more tired on the last 800.
Overall, the workout was not too too hard but harder than previous workouts- I had to push harder and was breathing harder as well. Yeah, running on tired legs is harder but it makes us stronger!

Weights afterwards.

I feel little sore now.