Here are few suggestions.....12 carbs is not very many, Atkins says 20, you may want to up your carbs, if you jog around this forum you will see that some people up them a bit, using good carbs, vegies and such and started losing again.

Also, you mentioned no weight loss, but have you measured, you have been swimming vigorously and lifting weights. Muscle weighs more then fat, easily. So, you should measure to see if you have lost inches.

One more thing, you may be eating too few calories or not enough fat with your calories a good way to track everything is www.fitday.com if you already do not. Eating low fat low carb is not necessarily a good thing.

These are just suggestions, I am no expert, there are however better educated people then me who may have some great suggestions for you.

Good luck.
Cindy