I used to be rational. Now I’m emotional.

A few years ago, I realized that I could do anything whenever I wanted. I was so rational and ignored my emotional reasoning (in a good way). I could study or work out when I felt lazy. I could bring myself to do anything. I felt powerful and disciplined. It didn’t require any practice; I just realized that I had the mental and physical capability to do all that, so I just went for it. Now I can’t do it anymore; I mostly rely on emotions to act and do something. How can I come back to how I was?