SAD ABOUT MLK OR JUST SAD?

Hello, hope everyone is well. I know yesterday was Martin Luther King day but I'm writing about it today. I've learned who MLK was every year in school as many others have and know about him. I felt so sad as a third grader knowing he got killed when he was such a kind man. Today I read about him again on 7 Cups and then I started crying, like bad. I've been too emotional and stressed because of finals and school and many other things, so I'm not sure about the exact reason I cried. How come this year I grieved like I knew him? I couldn't stop and just kept thinking about all he did, all his marches, his speeches, dreams, everything. And then I thought about how an inspirational human like that was murdered. Then the waterworks got filled again and I had to lock myself in my room for awhile. I really can't stop thinking about it and it's just adding more pressure on my mind and taking away time from my work(which I kill myself for right after). Like I said, I'm not sure why I cried. Am I just realizing what he did and how terribly his life ended, being older, or am I just too sad? Maybe too sensitive? Usually when I'm feeling like this I do tend to cry over anything but it might also be both cause I really wish I'd met him now. Also, two close friends of mine have faced recent deaths of a loved one and I grieved then also for too many reasons. Does anyone have an opinion on this? Is it bad or is it just my personality? Does it have anything to do with depression or stress? Is it weird to cry over someone you never knew and lived a long time ago? All opinions are welcome. Thank you for reading this.