So I was stressed out about a gig I did wednesday night (standing for about 5 hours). Usually after these, or sometimes my legs might be a little achy, but once I go to sleep it generally goes away. It is now Friday and my legs feel sore (not achy). Like identical to the feeling you would get after working out (DOMS), except that I haven't even worked out this week, especially not legs. Any ideas whats going on here?