If you were doing Atkins, which is where most of my experience lies - after starting eating low carb back in the 1970s, I'd suggest eating another 5 or even 10 gm of carb a day - after the first month that is what you'd normally be trying out, and you should find that your energy levels pick up, so you can be more active.
I'd check with you though that you are eating low carb foods, my personal limit is 10 percent carbs, as you might be, mistakenly, eating just a little high carb food - and that normally takes away energy due to the insulin response. It might seem odd that the same amount of carbs from bread, pasta or potato, even legumes, has a different effect if eaten as salad or low carb veges, but I have been told that it does, and found the same myself when I tested those foods for their effects on my BG.
I now know that all the foods which stopped weightloss are exactly those which raise my BG levels, so I do wonder just how long I have been diabetic.
If you check that your BG levels are not going high after meals with a few extra carbs then it is a good sign that your metabolism is getting back into balance - I found that after meal readings of no more than 8mmol/l were the turning point. After that my BG levels dropped (or bounced around like mad) so I knew that something was happening.