Possible trigger

Long story

I’m 16 now but when I was 12-13 I had a crush on this guy when I told him I liked him he told me he liked me too but as soon as I had admitted my feelings for him I lost them (which I wouldn’t tell him for another 1-2 years) he then proceed to ask for my address so “we could have a sleepover” which I thought was sketchy and I knew better than to give him address so i didn’t. Flash forward to a few months ago I tried to break off our “friendship” to which he begged me to please try and I told him that I had been but I just couldn’t do it anymore. He just kept begging and begging so I had enough and blocked him on everything. I was a little worried about him so I had my best friend message him and see how he was doing and he responded with “this makes me want to kill my self” we both started to freak but I knew while all of this was going on he was just being manipulative to try to get me to stay. Flash forward again to a few hours ago I was watching YouTube and I got a notification from Facebook that he had sent me a friend request.(I had gotten a new phone and couldn’t get into my old account so I had to get a new one and I must have forgot to block him) I instantly started to panic because my place of work and what my position is is on there (cashier at Walmart) and I’m afraid now that he’s going to show up at my work and try to talk to me but it’s not like I can just walk away from my register. I plan on talking to the manager that I trust whenever we both work next. I’ve even had a dream that he showed up to my work and ran around the register and gave me a hug that dream happened twice and both times ended with me waking up crying. I’m genuinely concerned for my safety but I don’t know what all I can do about it. I’ve thought about a restraining order but don’t know how that would work with me working at Walmart. One reason that I’m concerned is that he’s had a crush on my for years and has been possessive throughout the entire time I’ve know him