This way of eating is diuretic so I suppose it could lower your blood pressure. I think the answer is to drink lots of water - at least 8 x 8 oz glasses a day. I think deliberatly introducing salt into your diet could cause more probelms than it's worth.

Another point is that you may be feeling tired bacause the body is switching over from burning glucose as fuel to burning fat and it's not quite 'converted' yet. I think you need to give the low carb way of eating a longer chance to prove itself. Go light on the excercise until you feel you are ready.

I've found an increase in my energy levels since I've been eating low carb as my blood sugar isn't rocketing up and down all the time.

Good luck.
Robert