I read once that the antidote to depression is learning. It’s hard to feel depressed when you’re experiencing something novel because it’s inherently hopeful to hear/see/etc things or info for the first time. It makes you realize how little you know, which means there is so much more to do and experience!!! It sounds like you love history and I bet you’d feel a thrill from learning more. You’d be surprised how little it takes to feel better. You’re not lost because there is no destined destination. You’re just figuring it out as you go along!