Looking for experiences with Focalin for ADHD

To anyone who takes or has taken Focalin, how did it help you? What were your symptoms from taking it? I was on Concerta for my ADHD for a few months and it was fine at first, but I got immune to it quickly like with any other medication. So I was put on a higher dosage and even before increasing it, I got very nauseous and light headed from it and it made me feel very tired and almost lazy throughout the day from how tired I was instead of more focused and such, which made others pretty annoyed with me at my old job. So I was switched over to Focalin because many others have told me it's known to work way better than Concerta and my doctor said that it should help my fatigue as well. I just started it so I haven't seen results just yet, and I looked up some common symptoms from it, but I wanted to ask you all too, so I can see how it's affected others in this community! Thank you all so much in advance!