How do you know when to rest?

So last night we had some friends over. Eric was in charge of dinner but I did make some chocolate dipped strawberries and bananas, yum.


Looking at the pictures again I kind of wish some were left this morning. But nope, we ate them all last night :)
Anyways, I ended up not getting a lot of sleep and I have that miserable teacher test this afternoon so I hope I don't fall asleep during it. This morning I woke up and I debated for awhile about whether I was going to go for a run or not. On one hand, I had only 4 hours of sleep and it seems smart to conserve my energy for the test. On the other hand, I am training so I really need to keep on top of things. Back on the first hand, my legs are absolutely killing me. But on the second hand, I took a day off yesterday so I probably do not deserve another one. I finally decided to run around the reservoir because at least it is dirt instead of hard pavement. As I was running around I started to realize how I maybe should've waited until a little later in the morning. There was literally not a single other person there, which kind of freaks me out since I clearly watch way too many kidnapping shows. Then I thought, maybe I'll see Tiff (my best friend from high school who happens to live on the other side of the res) because she often walks her dog around there in the mornings. Two minutes later, who do I see? TIFF! Yay! This made my run significantly better (and not just because I got to stop to talk to her haha). In the end I think I ran about 2 miles, which is not great but considering it's better than nothing. According to the pedometer that Eric brought me from his work it was only 1.5 miles but I don't get how that is possible since the res has marks all over that say it is .9 miles around and I ran around it twice.
My problem right now is I really don't understand why my legs hurt so much. Even during this training I have rarely worked out for more than 30 minutes, which I would say is bordering on EASIER than what I was doing before. So what is the DEAL? I am all for a little, "it's sore but it feels good" but most of this does not feel good. Also, I am probably reading too much and everything is like, "don't do too much too soon!", "rest if it gets too hard!" etc. That makes sense and all, but at some point you have to push yourself or it's not a triathlon! Hopefully once I get some sleep I'll be able to do some serious training tomorrow and feel better about it. My legs will get some rest this afternoon while I tell the crazy MTEL company all that I know about being a Reading Specialist.
By the way, I am going to draw the winner of the giveaway when Eric is awake because I want him to take pictures of the process haha so we will either do it when I get back from my test tonight or tomorrow at some point. If you still want to enter, I'll continue to take entries until I actually draw the winner so go for it!