There are quite a few things that I become insecure about on a regular basis. My weight, my appearance, my intellect, my job performance, my writing abilities. It happens to all of us at one point of time or the other. Don't get me wrong, I am usually a confident person when I'm used to the situation, like going to work or writing an essay. I know I can accomplish both.
What I get most insecure about is if I've done it to the best of my ability.
I like knowing I did a good job. I like knowing I look appropriate for the occasion or pretty when I try on my outfit. (It's not going to be nice all the time, come on I'm in college, sleep deprived, and not rich enough to buy all the clothes or cosmetics to work with for half an hour in the morning.) I like knowing that I am smart or at least did a good job on the test that I studied my butt off for throughout the last week.
That doesn't always happen though. I've failed a test. I've definitely left my dorm room in sweats or without makeup more than I'd like to admit. I've messed up and made mistakes at my job that might be seen as common sense. I haven't been spit-spot perfect.
I don't really want to be though. While I'm overweight, I still like what I wear and how I look. It might take some time for me to find the right store or outfit but I can still look nice and pretty if I want.
I read a lot of books, but I don't really see the point in reading some stuff that doesn't interest me. I've tried completing Atlas Shrugged for over a year and I still have barely cracked the first 200 pages.
I have a new second job and have gotten told I was doing things wrong. I also have an awesome staff that respect me and are there for me when I need them. They help me in my inexperience and support me in the decisions I have to make to make the desk run smoothly.
I won't get everything right. Sometimes I won't try to get everything right. There is not enough time in the day to really worry about it though. I definitely have worried about it more than I needed to but that plays a part in the insecurity too.
Don't refute insecurity, embrace it. You are better than you know and while it might not always show, you have done your best. I definitely need to remember that more and I hope you will too.