Is everyone more accomplished than you or do you just think that. You need to spend 5 minutes a day increasing your accomplishments. No need to feel less accomplished.
You can feel more accomplished by
Accepting challenges.
Getting excited by these challenges.
Avoid apologizing for not being good at everything.
Reading business journals and creating new opportunities for your company.
Learning something new, e.g. advanced computer skills, and tell everyone about it.
Becoming an expert at some aspect of your work. Become so useful to your employer so that your company cant do without you. Make an essential contribution to your company.
Make an extra effort even if it means working longer hours.
Share your successes and setbacks with friends and family. Gain support and encouragement.
Give presentations on your new expertise.
Enjoy the praise.
If you are not passionate about your job, investigate new job opportunities in the area that you find exciting.
When you love your work and your results are appreciated, your confidence will grow. Start now with one idea only. Show the new confident you.