Replacing weed with alcohol is one of the most commonly made mistakes I've encountered. If you're truly worried about your cognitive abilities, alcohol is a far bigger threat. It is far more toxic to the body and mind than cannabis, and can even cause brain damage/memory loss at high levels over long periods of time.
If you really wanna take a break from pot, you're gonna have to keep yourself occupied with other things. It's when boredom sets in that most people go back to their DOC. Also, hanging out with stoner friends, being around pot, and feeling depressed, lonely, or angry are common triggers.
If you're looking for less potent alternatives, you could try hops (a cannabis relative), catnip, or passionflower tea/smoke, all of which provide a mild sedative effect. Other than that, you've gotta stay busy--work, clean house, go out and have fun, read, and do anything that you don't normally do when you're high. For instance, if your favorite thing to do is get blazed and watch a movie, DON'T sit around watching movies or you'll start to think "how much better this would be if I was high." Go outdoors, exercise, and stay active. And most importantly, stay AWAY from others when they're smoking.