If this sounds like a situation you've found yourself in, do something you love to do that makes you smile.
Write down your questions and feelings about something(s) in your life, then write down what you want to be the solution or answer for it to go your way.
Things you know you can do and you can get on with well, will make the solution you want to occur - happen for you. This will put a smile on your face - you'll feel relief because you'll start to know and believe that there is a lot to your capabilities.
Going about your thing(s) this way should give you the confidence you'll need to get on with it and do it or them well.
Also, to help give you confidence and to help to put a smile on your face - try putting your favourite piece of music on that puts a smile on your face and lifts your spirit.
While it's playing, have a little groove to it, to liven up your body, this will help your brain to work better. Then look into a mirror and say the question(s) and feelings you had, then read the answers out loud to yourself and while you do this, try to look yourself in the eyes, so your brain will feel the confidence and strength you have for doing this.
This will give you feeling that you can conquer whatever it is that's getting you down, you'll be able to do it or them with a go get em' vibe to your fine self.