I’ve noticed this now as it’s the second one I’ve done it with? 
My first one was in my Level 4 last year, me and my boyf were going through a bad patch and he left me, so I turned to my lecturer (let’s call him Dave). I was very inappropriate and was essentially in love with him. Like balls to the wall infatuation. I loved him, he told me not to move away to my boyfriend which I took as stay here with him, and told me he was single before telling everyone else he wasn’t single. We would ‘accidentally’ touch hands, and he took to me because I was so full on. Me and the boyfriend ended up getting back together but when I was talking to Dave before I left I asked him to meet me to go bouldering or something and he said okay, but at a point when he isn’t my teacher anymore. 
But then after I left he starting airing my messages and completely cut me out. It really hurt that he took such an interest in my personal shit and then left. Like boom, cut out, gone. Like he knew I was fucked up at the time, crying in lessons and he read my journals etc, but he carried on and still left and it fucks with me. 
I figured it was a one off, but then I started uni last week, and I’ve become obsessed with another lecturer (let’s call him Bill). I can’t let myself go too far with this because last time it really did break me and it’s horrifically unprofessional. But I hang on to every word he says, try to make conversation, dress up for lectures.
But he was only there for the induction week, and now he’s gone cause he isn’t my personal tutor. I kinda wanna take Neuro Psych next year so he’ll lecture me lol. (I won’t) 
But all day I’ve felt so shit and depressed because I’m not gonna be seeing him at all really. 
I don’t know what causes this and whether it’s a BPD teacher FP thing or whether I’m genuinely more damaged than I believe to be 😂

TLDR: I get obsessed to the point of loving lecturers and then get super depressed when they leave lol