Still Can't Act Normally

I know I talk about this way too much but my ex is the number one thing that bothers me in my life. It's not that he personally bothers me or that I hate him, it's just that I'm not very good at dealing with having an ex. At this point in my life, I'd like to say I'm 95% over him, and that other 5% I'm not even sure are romantic feelings.

However today I realized that I still act like a complete weirdo around him. I haven't seen him around school lately which has honestly been quite nice. Today I was walking to class with two of my friends when suddenly I saw him and his friend turn the corner and walk right by us. When I first saw him I told myself I was going to act normal but I'm not sure if I made eye contact with him or something because I suddenly started to freak out. I looked away and physically dodged him and sort of hid behind one of my friends. I was probably the only one who was aware of this because my friends didn't say anything so hopefully he didn't notice either. Our last encounter was really nice, a short friendly little chat at the grad party but this time it's like an alarm went off inside me telling me to panic. I swear no one else has this kind of problem with someone they dated over two years ago for only two months. I really, really wish I could act normally around him. Especially since I'm bound to run into him next year at university since we are going to the same school and doing the same program. Please just let me be a normal person around him so I don't come off any weirder than I already have.