Much has been written elsewhere, in scores of astrology books, articles, and blogs, about the negative effects of Mercury Retrograde. Even people who are not into astrology can get a laugh from exclaiming that "Mercury must be in retrograde" in response to something going seriously awry.
Well, I am not here to be the astrological version of Pollyanna; Mercury's Retrograde periods can, and often do, suck. Communication delayed or misunderstood? Check. Computer or mode of transportation broke down? Check. It took you five hours to get somewhere that normally takes half that time? Check. Having second, third, and fourth thoughts? I think you get the picture.
Mercury turns Retrograde tonight at 11:50 p.m. EDT, and will stay Retrograde till the 26th. Next week Mercury will oppose Neptune (which itself is Retrograde at 0 Pisces, but will be back in Aquarius in time for the opposition). Confusion, delusion, or disillusion may reign. You may remember to remove your rose-colored glasses, but not remember to open your eyes, 'cause dang, that Sun in Leo is too strong to stare at directly. You may be tempted to binge on food, alcohol, or other substances without considering your long-term health, or even how you will feel the next day. Even if you are a good boy or girl and take care of your physical body, ailments such as insomnia, poor digestion, foot, circulation, heart, or back problems may pop up anyway, and take much longer than normal to go away.
One inarguably positive effect of Mercury's Retrograde period is reflection. If you are introspective as a rule, Mercury Retrograde will not pull you out of your comfort zone, but encourage you to mull things over. However, if you tend to leap before you look, or just run off at the mouth without an inner editor, you will definitely feel more restricted...and as you champ at the bit, keep in mind that this may be to your (and others') benefit. Sometimes it really is best to do nothing.
Around the 16th, with Mercury conjunct Venus and the Sun in Leo, you may find the opportunity to mend fences with a loved one in a romantic, dramatic manner. Creativity will also be very high, and you may also be able to successfully revive, or revise, a creative project that had stalled.
That said, break a leg...but not really.