Have you ever faced harassment at work?

Or at the very least, someone making you uncomfortable? I’m going through it currently; long story short, it’s an older male co-worker (mid to late 40s, maybe early 50s I think; I’m 26) who constantly stares at/watches me, is always trying to be around me or in the same area of the room as me, letting out loud, depressed sighs around me, among other things.
It’s crazy how you can go through life hearing about these things but never fully “get it” until it happens to you.
How did your situation resolve?