I think that can be a sign of high estrogen, but I doubt that at 4 weeks in on that dose it would be causing it. If you're working yourself up over it, as I tend to do with any meds, it helps to know that what you're taking is lower than regular birth control doses. If the estrogen is in fact causing it, it's probably just your body adjusting to it, as it's not a high dose, and riding it out would be the way to go as it will soon settle. Also, if you're not already fully post menopause, and perhaps even if you are, you're body may still be having surges and crashes in hormone levels leading to these feelings. I think I have that problem even a year into hrt. Adding a constant supply of estrogen can lessen the extreme dips, but doesn't necessarily stop the ups and downs from your own body producing hormones.