I'm going into my jr year of high school and am a male with an xc 5k pr of 17:28. So about 6 weeks ago I ran a 5k time trial, and got an 18:07. This was solely off of flat easier runs and about 35 mpw. I've bumped up to 40 mpw now, and the past 2 weeks I started to add a speed workout (8x400 at 75 2 min rest, or 6x800 at 2:45 with hills and 2 minute rest). These workouts felt quite easy, especially the first one. I also run a tempo run every week for 20 mins at about 6 flat pace. This pace feels suitable and I feel like I could run another 1-2k at that pace, but no more than 3k at that pace. I do an 8-10 mile long run. The rest of my runs are either 7 miles at 7 flat pace, or 5-6 miles at about 7:45 pace (these are typically group runs). I just ran another time trial at the exact same location and ran an 18:07. It was hotter this time at about 87 degrees. I also woke up early and walked 3 miles in mud for work today. What should my move be? If I keep doing what in doing, will I improve? Thanks.