Low carb? You need carbs to build strength.
48 hours should be plenty of time for your muscles to recover once you've gotten into the routine.
Try switching up the exercises you do, and vary the order in which you work specific muscles. Changing it up is the easiest and most successful way of busting a plateau. Also, I'm a firm believer that you shouldn't take any supplements (aside from protein) until you hit a plateau, and then use them to help you bust through.
If you're looking for more definition, try to slow your reps down a bit if you haven't already, and make sure you're doing them completely and thoroughly without any bouncing or cheating. Increase your number of reps to as many as 12 if you haven't already. If you want definition, that's the way to go. However, if you want to gain mass, you can lower it to as little as 6 reps per set. Some people can do both (cut and add mass at the same time); it all depends on what your body is capable of, but I've found it's much more effective to concentrate on one goal at a time. But that's just me.
Lee Priest works out in his personal gym in the Outback, in scorching heat, to tone down. One of the few guys left who gets uberfat in the offseason, then cuts it all off with great results. You could always try working out in 100+ degree heat, but I'd say the health risks involved there probably wouldn't be worth it.