I would suggest that repeats of 200, 400 and maybe 600 meters are much more appropriate for 5K training than mile repeats.  (Even if you're doing mile repeats, the recovery interval shouldn't be 2 miles.  Probably more like 3 or 4 minutes.)  Take a look at this "Advanced" 5K training plan from Hal Higdon.

http://www.halhigdon.com/5K%20Training/5-Kadv.htm

This is closer to the training you should be doing.  The 10K you did sounds close to a typical tempo run.  This plan seems to peak around 35 miles per week.  You're doing more than that, which is OK, as long as you're careful to get enough rest/recovery time.  Good luck.

Len

Im a 1200 meter man myself : )  The lactic acid build up that happens from the 800-1200 meter mark will make significant improvements to your 5k times.  I have put together quite a few workouts on my website including some from the Nike Pro Team that one of my buddies runs for:

http://eliterunnersworld.com/runningworkouts

No need to stop running interval workouts because you are training for a marathon.  I've used 5 x 1000 intervals in training for all my marathons. Most marathon training plans, beyond the beginner level, include at least one interval workout a week.  You can do the long runs on the weekend and the interval workouts during the week.