I constantly do this. Create a deadline for my creation, realize that what I actually want to do will probably take me longer than the deadline, then I have to make a decision to change the deadline or just do the best I can with the deadline I’m given. Sheesh!
A perspective that really helps me when I feel lost or confused with life is imaging my life if my parents died - everything else becomes less daunting and the things that were stressing me out become much smaller and easier to tackle.