We all have different workout schedules and what works best for us. Last week was my first forty mile week. With that did three things differently started to bike; did about ten miles on the bike. Second thing was went swimming from four miles for the week to six miles. Then also walked seven miles when not running; did all this from Sunday to Sunday. Rested Monday and then went out for a ten mile run. A tough run with the legs feeling like that they were rocks. Though last week felt fine was wondering though does it seem body is just say relax this week?
Im not surprised your legs feel like weights and you feel tired, I think you did alittle over training last week.
You might want to build up to that slowly so your body can get use to all the phyiscal work over a month or two of training . Im also sure your body is saying give it a break, with that I would wait a couple more days and then ease slowly back into the running over the next week or two..
It's not only about finishing, its about finishing healthy!