Self doubt: how to counter it

Something that I experience a lot, and I'm sure others do too, is self doubt and fear of failure. Being a perfectionist by nature, I often scared and anxious when I am given something new to do. Like at the moment, I've been asked to cover for someone at work who is taking two weeks leave. Basically I have to take over her post and do most of the tasks that she's usually responsible for. 

Firstly, let me say the things I'll be doing is outside of what my job entails, so most of it is completely new to me. I've had a couple of training sessions with the person about to go on leave, but it was all a bit of a rush and an overload of information.

Here's where the self doubt comes in. Even thinking about it now, I can hear my thoughts heading in the general direction of: you don't know what you're doing, what if something goes wrong, you'll end up messing things up for them, they won't be happy with your performance... you get the idea.

So how do you cope when thoughts like that come up?

For me, rationalising helps a bit. Looking at the situation and trying to view it objectively. It's true that there is a lot that I have to learn, but really, I'm not a superhuman and they know this. Whilst they expect me to complete the tasks assigned and have hope that nothing will go too wrong, they also know that I don't know absolutely everything about the role. And if there's anything I'm not sure off, there will be someone who I can ask and will be able to help me. 

It also helps to think about what the worst scenario could be. Even if that happened, so what? I'm not saying that you should take a "who cares, nothing matters" attitude to your work, but thinking about the worst scenario helps to put things into perspective. For the work I have coming up, I know that I have some knowledge of what I need to be doing, the worst thing that can happen is that I start doing it and realise there are things I don't know how to do, which could prevent me from completing the tasks (as one thing can affect another in the task I'm doing). But even if that were the case, the only thing that will happen is I will need to ask someone for help so that things get done properly and on time.  In any case, the person helping me could be in the same boat as me in that they might not be 100% sure of what to do either. 

When you are feeling anxious about having to do something, it's also important to stay in the present. Because in that moment, you are not even doing the thing that you are worrying about. You may be able to prepare for it, and if you can, then by all means, do it. But once you've done what you can, take a step back. Know that you have done what you can for now and that worrying anymore about it won't really make a difference.

Try to be optimistic about it as well. This is definitely easier said than done, and I am probably an optimistic pessimist at the best of times. But the only way to change your mindset is to practise and keep reminding yourself. As much as you may doubt your abilities, when it comes to work or other tasks, it is unlikely that someone will ask you to do something that you are incapable of doing. Sometime it may be the case the things are just dumped on you (see, the pessimist in me), but chances are other people believe in your abilities and who knows, maybe you are. You won't know until you try.