For me it helped a lot to drink a lot of Chocolate ensure (yes ... it might not taste good to some).
I had starved my body of so much nutrition that it caused huge fatigue and weakness.
It may depend on how much for how long you drank before stopping. It is also a good idea to see your doctor because there can be some very serious consequences of long term drinking and they can run tests and provide fixes for many problems.
Let us know how it goes.
