Ecclesiates 3 talks about a time for everything, and a season for every activity under heaven. A time to be born and a time to die. A time to plant and a time to uproot. A time to weep and a time to laugh. A time to mourn and a time to dance. A time to search and a time to give up.
Choosing to let go doesn't mean you've failed, you're giving up, or you're forgetting it. Letting go means that you are recognizing that God is in control (and not you) and that there is a bigger purpose ahead of you. You won't have all the answers at first, but as you take steps of faith forward the Lord will make things clearer for you.