Whether or not you can work two jobs at the same time is dependent on more than how well you can juggle multiple responsibilities on a shoestring timetable. You may face legal repercussions, health and happiness constraints, and potential problems with your primary employer.
Think back to the mountain of paperwork you signed when you accepted your current job. If one of those pages was titled "Non-compete Agreement" and was followed by a lot of legal terminology, you likely signed a non-compete agreement that limits your legal rights to work a second job. Typically, non-compete agreements limit your ability to work in a related job while employed with your current company -- and possibly for a period of time after leaving employment. However, the agreement may state you cannot moonlight at any job while with your current employer. Before taking a second job, it's time to dig through that employment paperwork and find out exactly how your employer will react to a second job.
Working two jobs often means making sacrifices. If you would rather sacrifice time for exercise, sleep or nutritious meals than cut back on social events, your health may take a nosedive and make it difficult to work two jobs. Keep in mind as well that your mind will be more receptive to a second job if you can mix it up a bit. Bookkeeper by day and bartender part-time evenings will give the analytical you a break while still replenishing the pocketbook with much-needed green.
Working two jobs can be a stressful undertaking, especially if you do not enjoy what you are doing. While working two jobs may be necessary to make ends meet, you will find it much easier to actually manage the endeavor if you enjoy what you are doing and see you are striving toward a goal. Make a visual representation of your goal, such as a dream board or a separate accounting of how the extra funds are used to pay down debts or to afford that luxurious trip you've always wanted. Reward yourself for meeting mini-goals along the way and you can amp up your happiness level.
Be honest with your employer. Whether you signed a non-compete agreement or not, your employer may find it disconcerting that you are now rushing out of work and are no longer available for special assignments. Your time-management efforts may be viewed as losing interest in your job. By discussing your situation and reaffirming your commitment to your primary position, you can cut short any doubts your employer may have.