Ok so I am a newbie I am in about 5 weeks of training just trying out a 3 mile I am finding on certain days I can go a whole mile and half without stopping and then the 2nd half I do about 2 min run and 1-2 min walk alternating not really going by the book just testing the waters to see how far I can run without walking - now today was very humid dealing with the effects of tropical storm Isaac early morning run I fell behind started with run at 4 min, then had to walk 2 min run 2-3 min alternating maybe only did a total of 2 miles within 30 min.  is this normal? not sure what to expect much harder this morning I felt tired waking up so not sure if it's that or on top of humidity.  I have not yet invested in a heart monitor yet that is to come I did try to pickup my speed - can someone tell me if I am on the right track if days like this happen or do I need to step back into the program and work up again--- ANY HELP/ADVISE APPRECIATED.