You NEED to lower your mileage. 80 mpw for someone in his first year of running is not just overkill, it's insane.
1) You are limiting your own potential by taking advantage of high mileage early when it's absolutely not necessary. You could improve and run the sub 16 5k on probably 50 mpw (Grant Fisher ran low 14s on 45 mpw). 50 mpw is enough for you to progress big time, you will strengthen your heart, bones, muscles, tendons, joints, ligaments etc.
2) Injury risk is VERY high when you run mileage without the body being prepared for it. You are lucky that you were able to stay healthy so far, but keep in mind an injury is going to cost a lot of potential progress, especially if you have to take a long time off.
I can see you run sub 16 in a few months, even with lower mileage. Do 50 mpw, which is already very high for a 1st year runner / Freshman (even if you are in your 20s or 30s, your body is a Freshman in terms of how adapted it is to the stress of long distance running). 1x long run, EASY, 1x tempo run which should be comfortable and 1x longer intervals on track, like 1k at 5:20 or miles at 5:35. Trust me, this is enough to get to sub 16.
Then you can use 60-70 mpw to get to sub 15, and 70-80 mpw to get to a time in the mid 14s if you have the talent for it. Take it slow, you seem to be quite talented (high injury resistance, very quick progression) and should make most out of it with proper, smart training.