I agree with Pink: as our health starts to wane from years of misuse, it will take some work and it's not just one simple cause usually. Colon cleansing is a great way to start, then you may want to read about Liver Flushing and consider starting those. This is all a process; some people in the quest for health do a Liver-Flush monthly. Some people do The Master Cleanse 4x a year for a more dramatic cleanse (it's a liquid fast). But def start with the colon and look at Liver Flushing for continued digestive health. Good luck in your quest.
FYI - since learning about alternative medicine stuff, doing some cleansing, and changing my diet, I feel better than before cleansing while on a bad diet. I had started to feel old and hated it - I wanted energy back and now I'm back to how I was before I started eating really bad... now I want to get to where I was when I was younger! We should feel energetic and vital!