Is your mind not feeling quite as sharp these days? Many women find themselves very frustrated by the onset of "pregnancy brain," which makes them so forgetful that they might not remember what they're talking about halfway through a sentence. Your ability to concentrate and pay attention to tasks may also be affected. Doctors are not sure why this happens, but it's likely to be a result of hormonal changes. It may also happen because during pregnancy you're focused internally: you're going through such a major life event, and there are so many changes happening to your body and lifestyle, that you simply pay less attention to other things.
As frustrating as it is, this tendency to forgetfulness is only temporary (although it may last into the first year of motherhood). In the meantime, try making lists at the beginning of each day and check off tasks as you go. Delegate at home and work when you can and, for once in your life, don't try to multitask. Focusing on one thing at a time will help you remember and achieve more.