Switched from levothyroxine to Synthroid, now anxiety

I started out on 25mcg of levothyroxine. My body adjusted well to it then within one month I was switched to Synthroid 50 mcg. I am not adjusting well at all to the name brand. Could it be that the brand name is more potent and my body needed more time to adjust. I couldn't take the anxiety any longer so I broke the pill in half and I feel better. I also started taking it at night just before a go to sleep around bedtime. Anyone have a similar experience. I am newly diagnosed and need to know what might be going on. Please, your insight is greatly appreciated.