You need some supplements. Get some glutamine for starters, that is what gets depleted and leaves you feeling weak after working out frequently. When I started working out I was having the same problem. I was weak as kitten after a while of daily workouts. The glutamine is good but I use a pre workout called "explosion" and a post workout called "myobuild 4x" and they work great, you can get glutamine and "explosion" at Walmart.