Effect of long run of 5 miles

Not good, the effects are not good.
I reached home exhausted. Stretched, bathed, went to NB's place for breakfast. Returned home with a slight headache which got worse. Felt fatigued. Went to sleep, didnt really help.
So presently, I am not having any particular ache (except for the headache which is much better with the ibuprofen), but am feeling like there is no energy in me. Talked to NB, she is ok except for the knee issues she had in the morning. She returned from the run, made breakfast for family, took her kids shopping, came back and cleaned the house and slept for 40 mins somewhere in between...phew!!
When I was running 3 miles in dec, I kept saying that I could go a little more, but today, after the 5 miles, I am totally depleted. Before the run, I kept saying I would do 6 miles next week even though according to NB's plan we are supposed to do 2.5 miles. But after the run I am going to take her up on her proposal to do only 2.5 miles next week.