How many days in a row is it acceptable to not to run, when training for 100miles?

I'm sure the answer is not mine, 10 days. Ever since Sycamore Canyon 50k this is how i feel things have been going:

My intention was to take a few days of active recovery. I hiked out in the mountains Sunday and Monday. Then I was to start running on Tuesday again. Then Tuesday came and went and many other days. Why did I not run for 10 days...I have many excuses, maybe some valid, maybe none valid, all and all looking back at the last 2 weeks it has not been fun. I have not been feeling well. I am tired. My body hurts. All I want to do is sleep. 

After having a headache for 5 days, Monday evening it was so severe I couldn't work, my head was throbbing and I couldn't hold a conversation without wincing, I decided to take myself to urgent care. My headache was making me so nauseous I thought I was going to throw up in the waiting room. 1 liter of IV fluid, a zofran and IV toradol later I was feeling much better. End result: Who knows? Stress? Dehydration?

Finally on Wednesday I knew I had prolonged the inevitable, back to running. It was meek. Back at it on Thursday...I was struggling to finish 8 miles, so much so a 1/2 mile from home, I tripped on a root and dove face first into the dirt. I was covered in filth. I was just sweaty enough to to have this fine dirt stick to my whole right side. I was a little shaken up from the fall, it caught me off guard. My right knee felt a little stiff and my right shoulder hurt from me trying to unsuccessfully catch myself. I was so dirty, I took my clothes off in the shower. A couple of hours later my knee was swollen and I was feeling sick again. Thursday night I was home in bed by 7p and slept until 8am. Luckily for a 4 day weekend and the bad weather in Big Bear (I was  planning on leaving for a camping trip early this morning) I lounged around all morning. Still tired and no energy. But ambitious enough to go to a pilates class, then a run, then a hot yoga class. Well, I made it to the pilates class then to bed for a nap. I again am feeling ill, slightly nauseous, sore and way more tired then I should be.

I'm trying to drink a lot of water and think I'm hydrated enough. I just seem to have some sort of bug that I can't shake. Its starting to get me down, this weekend is a big training weekend and the next is another 50k. For now the plan is to just keep moving forward. Run until my body says "no more" and just hope I can hold onto  the fitness I have already developed. Its hard because I feel slow and feel like my training is making me slower, I should be in the peak of my training and feel like I should be seeing results, and I don't feel as if I am. I need to remind myself patience is key. I have to have confidence in my training. Take cues from my body when I need to rest. 

I'm going to keep struggling up this damn hill, because I know the at the top there will be something more beautiful and rewarding then I expect.