I started taking 10mg about 4 weeks ago and 2 weeks of taking the medication I wasn't feeling any better so I was told to take 2 10mg, I then lost the samples while moving so my doctor called in a prescription. I didn't read the bottle well enough and was taking 2 pills a day thinking they were 10mgs each. I then found that each pill was 20mgs and I had been taking it for close to two weeks. I felt much better. I felt like my old self and was becoming alot more active. I wasn't sure if this was a harmful dose so 3 days ago I went back to 20mg and I've noticed a change already, I feel the same as I did when I was taking 10mgs.I'm way to tired, have no energy and feel really down and blue. I'm not interested in anything.