Sometimes your system needs a reboot. Mine does and I am doing a one-day liquid fast as I write this. Did you know that 60% of your daily energy consumption goes towards running your digestive system and the digestion of solid foods? That only leaves 40% for everything else - work, play, heal. If you can free that 60% up for a short period of time by refraining from solid foods for a day or two it can do wonders for cleansing and healing your body. Drinking lots of liquids during that time - vegetable juices, green juices, fruit juices always in moderation because of the high sugar content, broth, lemon water with a bit of maple syrup, some tea, lots of water - literally reboots your system, cleans you out, gives your digestive tract a break, and frees up that energy for healing your body.
It's interesting to note that many religions include fasting in one form or another in their rituals. Some people are religious about regular fasts (pun intended), such as a liquid day a month; some people fast for two or three days whenever they feel their system needs it. Fasting is a time honored practice that makes a lot of sense, although it's not indicated for everyone (so make sure you consult your health care practitioner for advice if you've never done this and have doubts or questions).
Why not give it a try? It will leave you energized.