Don't worry about it, as long as you complete enough of the things you need to ensure that you don't starve, that is more than enough. The rest is just enjoyable experience and a chance to learn, the butterfly will never build a great high nest like the toiling ant, but it sees vast worlds the ant can never dream of, and in the end both end up dead. Failing is not about how much we don't achieve but how realistic our targets were in the first place.

Also remember that half the time we fail, it is because as well as the difficulties there was also the daunting magnitude of the task as a pychological preasure, break big jobs into small pieces, be prepared to leave them and come back later.