Don't let the talk about talent discourage you. I went from running 4:41 for the 1600 in high school to a 30-minute 10K 4 years later.
Things I learned along the way:
1. Increase the miles. I went from 40 mpw to 60 mpw. 6 weeks later, my 10K time dropped by 2.5 minutes. Increasing it to about 80 eventually helped lead to another 4 minutes coming off. In your case, I don't think it's too late to increase the miles for this year. You just have to be smart about it. You might consider a 10% increase per week for the next couple of weeks and hold that through the conference meet.
1a. Consistent running is better than really big days or weeks followed by low weeks. When I did my best times, I aimed for double-digit days everyday except Friday. I didn't have extensive long runs, but I also didn't have any real short days. I was pretty much 8-12 miles everyday.
2. The repeats are too fast for your current fitness. I agree with those who suggest a higher volume. If you don't want to use something like "Daniels' Running Formula" to determine your paces, you could always run at 10 seconds per mile faster than current race-pace for your repeats. That gets you used to a slightly faster pace without killing yourself.
3. Don't totally neglect speed. You can easily add in a mile's worth of strides at the end of a run. That does two things; it increases the number of miles per week and get your legs used to moving fast when tired.
4. Tempo runs are huge for the 5K-10K race distance. I did 4-mile tempo runs about 20 seconds per mile slower than race pace. They really gave me the strength to hold my pace over the last couple of miles of a race. After several weeks of tempo runs, I ran a hot, hilly 10K. Over the last 4 miles, 3 of the miles were run in exactly the same time and the 4th mile was 1 second slower.
The coach pulling you from your workout was a good thing. I did the same thing this morning to one of the HS runners I coach. I didn't like the way he looked during yesterday's repeat session. He has a tendency to push himself too hard, so I made him run with one of our slower coaches this morning in order to hold him back and let him recover. He didn't like it, but it beats him coming down sick or injured because I ignored the signs.