Is my crazy ex girlfriend stalking me, if so what do i do?

So after the breakup which happened about 15 months ago and I discovered she was a cheating ***** I blocked her on everything, she then went on a campaign of asking all of our mutual friends about me, along with sending me a vile email which I just trashed and constantly trying to find other ways to piss me off. Anyway I got over her relatively quickly, another girl I developed a crush on showed me there are better people out there, and despite her emotional abuse and manipulation of me during the relationship I have done my best to just get along with my life. Anyway a few months ago a she tried to trick a mutual friend of ours to giving her my number, he didn t and discovered it wasn t for her alibi of hers claiming it was to "set me up with a girl" when she hasn t talked to me or anything for the best part of a year. Few weeks later my friend and I were at the pub and he said she keeps asking questions about me, along with spilling a lot of weird **** about her, and lies she told me during the relationship which was pretty much everything that came out of her mouth during the relationship, not to my surprise at that point. Anyway about a month ago now I came back from the hospital as my mum was ill, literally she was in a parked car with some other guy about a 30 seconds walk from my front door. Most recently last Friday I got off the bus at my bus stop, she was at the bus stop there waiting, soon as I got off she got up and headed towards a bus which had been there...