How do I stop caring about what a person think of me ? I'm having a really hard time right now with a specific person and I don't know how to deal with it. Everytime I see them I tell myself all the bad things they probably think of me. It makes me feel horrible. It also makes me feel so sorry for them that they even have to see me, be in the same room as me... We used to be very important to each other but we stopped talking and now we just ignore each other. Still, we share the same group of friends so it's impossible for me to ignore the situation. 
I have no control at all over my thoughts, it's really hard to just "not care". All I do is repeating these bad things like "They don't want me here" "They're probably so sick of me" "They probably think I'm annoying" "They hate me, I'm sure they want me to leave" etc. 
Does anybody know a coping mechanism, a way to stop these thoughts, anything that can help ?