after a month of straight cardio i decided it was time to start muscle training.i put myself on a schedule which consited of my weights and abs with 60 min.of cardio at least 5 days a week.well,after a week now i've noticed that i'm getting fatigue after only 30min. i'm wondering if thats normal or am i just doing too much cardio and i should give my body a break? i take vitamins,extra protein, and eat regularly to keep my metabolism going.any advise?