We're always espousing the importance of work-life balance, because it's important to have a healthy mindset. Although anxiety is generally associated with being a negative feeling, a New York Times piece by professor Robert Frank of Cornell University's MBA program says that worry can actually motivate us and push us to be more successful. In fact, evolution has actually programmed us to become more competitive when we're worrying. Frank says:
In [Darwin's] framework, the brain has evolved not to make us happy, but to motivate actions that help push our DNA into the next round. Much of the time, in fact, the brain accomplishes that by making us unhappy. Anxiety, hunger, fatigue, loneliness, thirst, anger and fear spur action to meet the competitive challenges we face . . . Within limits, worry about success causes students to study harder to gain admission to better universities. It makes assistant professors work harder to earn tenure. It leads film makers to strive harder to create the perfect scene, and songwriters to dig deeper for the most pleasing melody. In every domain, people who work harder are more likely to succeed professionally, more likely to make a difference. The anxiety we feel about whether we'll succeed is evolution's way of motivating us.
This reminds me of a recent quote by Indra Nooyi, the female CEO of PepsiCo, who spilled the secret to her success. She said, "I have an immigrant mentality, which is that the job can be taken away at any time, so make sure you earn it every day." Although Nooyi is already the head of a billion-dollar company, she still worries about her position, which pushes her to succeed day after day. If she has been complacent and happy about her job, there will be less incentive for her to work hard.
Actually, seeing as our economy still has a lot of recovering to do, the sentiment of possibly losing your job might not be too unrealistic. However, you need to make sure that this anxiety does not eat you up inside, and manage it properly so it does not manifest into extreme symptoms like panic attacks.