How can I find out if someone has paid for a private investigator to follow me?

I have a protection order against me by my ex and I feel like I'm the one being harassed. After him taking me to court and he appealing it and winning along with so many other proofs I feel like he is harassing me and out to get me and I'm scared of him and I don't know what to do and he knows things and I'm not allowed to contact them but he knows things about me and what I do and I don't even live anywhere around them or go to anywhere around where they live I'm two counties away and I'm on my own business I stay away from them but at the same time I thought there's more going on