Random guy approached me with a knife

I went to mcdnolds before and I was walking back and some old man stopped on the other side of the rd started acting weird he walked a bit stopped again and pulled something out his trousers was a screw driver or a knife I don’t know him he didn’t say anything then I turned around started walking fast but he started walking fast towards me then stopped again he was distant away from me he pointed it towards me and started shaking it he didn’t say nothing tho I turned around said wtf u doing u nearly gave me a heart attack so I went in someone’s garden and banged on there door I was shaking my whole body froze I rang 999 and hid in the garden in case he came back police came then they went looking for him but I physically can’t speak I’m in that much shock I’m 19 years old I live on my own and I’m in the uk any form of weapon or object that can be used as a weapon is illegal times like this u wish we were allowed guns or tasers