I have been on Synthroid for about 15 years and have noticed that if I miss one dose, I feel great the next day. I have more energy, and more stamina throughout the day. If I miss any more than one day, I'm super tired. I have my TSH, T3, and T4 checked regularly and have felt fatigue and every other common hypo symptom since I was diagnosed with Hoshimoto's 15 years ago. Nothing seems to make me feel better, other than missing a dose of Synthroid from time to time. Has anyone else experienced a similar scenario?