How should my body feel after running 20 miles the next day?

Just go by feel.

What have you eaten?

The day after your long run should be an easy day. Unless 6:00-pace is easy for you, you shouldn't be running that fast unless that is easy pace for you.

The day after your "longest run ever" you should do 5-10 easy, unless you are running under 60 mpw, then you shouldn't be running that far period.

The day after any hard effort (intervals, tempos, long runs) you should run on the flattest courses you have around. I have a feeling that you are the kid that ran up mountains every day but had a 4:54 mile PR.

yea that is me, im a fag, im getting better about running fast all the time, i did 11 miles with some diseal guys and we averaged 6 flats, that is probably unncessary info but a 4:54 is so weak for a collegiate athlete. Yea i want to break 17 and maybe get to 16:40

yea give me some advice on food and stuff too, sorry i ask alot of questions. I had to take a month off from over training, it sucked i go to the point where I could not finish 6 miles without walking and my body fat wouldnt register and I was already at 3 percent, i had to get some blood work and shit, it was preety lame and I never will do that again. But I guess I really haven't learned my lesson because I just went out and ran 21 miles and then ran fast the preceeding day. When I get in a group I almost treat it as a race, so i need to train solo

Didn't say you were a fag, didn't say anything negative, just said that you can't run up mountains every day.

6:00 pace is very hard for a 4:55 miler. Are you being coached by a college coach? Try asking them for a schedule. If not try this:

Su: long run 12-15 mi for you

M: 5-10 miles easy

T: 7-12 miles hard

W: 5-10 mi easy

Th: 7-10 mi fartlek

F: 10 mi hard

S: 5-6 mi easy

Start with the low end of each range. That would be 50 mpw at the beginning. As you progress lengthen the long run first, then the hard days and the easy runs last, you will move up to 60 mpw and then to 70-75. This is not a magic schedule, just one that worked for me one December to March when I ran 4:25/9:30/15:37road one winter in high school.