Without knowing what the drugs are, I can't really comment. Some hormones, such as would be used to suppress ovarian function ... can have increased blood pressure, fluid retention and weight GAIN as a side effect. Also, without knowing what you're eating .. for example .. salty processed meats and cheese, or nitrates in bacon, ham etc ... can lead to increased blood pressure. If you weren't taking medication for your blood pressure, I'd be tempted to say cut out salt, and use a salt substitute containing potassium chloride, and take extra potassium as a supplement. However, some BP meds can cause you to retain potassium .. so not a good idea to take extra!

The amounts of protein one normally consumes in a day with low-carbing isn't enough to stress the kidneys, unless you've actually been diagnosed with kidney failure. And protein is protein, whether it comes from vegetation or animal, as far as the kidneys are concerned.

Do drink lots of fresh, plain water to keep your kidneys flushed, and also to flush out any other toxins and wastes, which could be contributing to the headaches and fatigue.

Sorry I can't give a better answer, but without knowing the details, it's hard to say.

Hope your surgery goes safely and well, and congrats on the 18 lbs so far, that's great.. .. Weight loss alone, whatever the means ... will bring great improvement to your blood pressure, which is why I think the problem is side effect of other things, and not specific to low-carbing.

Doreen