It is a common symptom of those who start a low carb diet (or really a just fewer carbs diet) to have about a two week period where they feel like shit or just a bit off.
I think one of the lesser talked about fat issues is stress and pressure. Say you are not hugely obese but need to drop 20-30 lbs. You do your research, you know what to eat and realize you are going to need to plan more and cook more. You also realize that you need to do a bit of exercising, but having done your research realize also that you can't just go balls to the wall from the get go. So you make time for walking, yard work, playing with the kids, but not too much because you need to do some meal planning. Things are going good for a few weeks and you have dropped a few lbs, but work has some deadlines, kids have some events, its raining, you are having some guests over, etc.
You fall behind, but you catch back up after a week or so. But there is more interference, its almost seems like there are forces at play trying to prevent you from living a healthy lifestyle. You soldier on, but temptation is everywhere-happy hours, beer after yard work, eating out. You have bills to pay, idiots to deal with, traffic, poor sleep, and you just want to chill when you get home, but you go walk and try to shoot some baskets. The next morning that ankle injury you in college is acting up. you need to adapt and change plans or a take day off.
So this is just some pressure to lose a few lbs, but the tougher part is dealing with stress in the modern world, which has also gone way up in the last 40 years.