To be doleful is to be down in the dumps, to have a hole in your soul, to be full of woe.
Doleful has nothing to do with a doe, a deer or a female deer. Unless one of those animals has a really sad look in its eyes. Expressions can be doleful, ditto a song or a set of circumstances. You can use the adjective doleful to describe something that is bringing you down, that makes you want to give into gravity or crawl into bed. Doleful is pretty much the opposite of how a ray of golden sun can make you feel.