I am on Concerta and went through the euphoria and noticed it was hard to focus again too. I thought my dosage needed to be increased. I did have some headaches but the big thing was I could hear my heartbeat in my ears and my heart was beating fast. So, I went to the doctor the other day and my blood pressure is high. Turns out Concerta and other stimulants like Ritalin can make your blood pressure go up. She increased my blood pressure medicine and I am doing better now. You might want to check your blood pressure to make sure that isn’t what is happening.