Ex Girl friend, still got feelings? but how to defy the impossible?

Well I met this lovely girl about last year february started going out in the beginning of march, broke up about novemberish due to us going to different universities and not having much time for each other. Well she apparently has a new boyfriend and according to our conversations they have gone pretty deep in a short amount of time, for example in her words " we already have $3000 saved up for our kids" well i don't know if she said that to rub it in my face or they actually do, and from what i know about her she rarely lies but also loves to make others jealous so its 50/50. All in all i just started a new job and out of now where, BAM shes at the work table behind me.. caught me off guard, wtf do i do? should i try ruining her relationship and get back on her.. because atm im totally ignoring her and shes doing the same.. our shifts ended at 12am and i had a ride coming but wasn't here yet, i knew her car was still in the parking lot waiting to see if my ride came or not then she left. so i don't know whether that indicates sympathy or she still has feelings but i know its close to impossible to get her back and perhaps ignoring her is the best way to just make my money and move on