I dumped my boyfriend and now I am scared

Last Friday I decided to leave my boyfriend of two years. We were fighting a lot and I just felt it was the right thing to do. I don't think he fully understood or believed me until a few days ago when it finally clicked that I wasn't coming back. It may sound cruel but I changed my number and deleted social media so we wouldn't have a way to communicate. That's when he began emailing me. He emailed me several times to meet him and I refused so he showed up at my work. He was hysterical and sobbing and wanted me to get in his car to talk but I refused. For one I didn't have time as I was at work and I also didn't want him trying to convince me to give us another shot. After that he left and threatened to kill himself. I truly believe he is capable after seeing how upset he was so I called his mom to check in on him. He ended up being ok but he promised to try again when nobody would bother him. Today he admitted to driving by my house a few times. He said he is going insane and should be locked up. That hes obsessed with me. I am truly afraid he will either kill himself or do something to me eventually. What should I do? I am confused and worried...