Making progress on longer term goals can seem daunting. Heck, short term goals seem that way too. Try not to think in terms of bigger buckets of work, but rather the next actions (more specifically, the next immediate action) you can take to move the work forward.
This is one of several concepts covered in David Allen’s awesome book on productivity, Getting Things Done. Allen’s method forces you to think about what can you accomplish next, versus the frightening backlog of what may follow after that.
The next time you are struggling with prioritization, take an inventory of what you have to do, and then identify the very next thing you can do on each of those to move them forward. Then do it again. And again.