sorry this might be long but i really need someone else’s opinion. 

so basically i started a new job not too long ago and met this person there. i instantly felt a connection with them and now they’ve unfortunately become an obsession to me. they also suffer from mental illness which means that they aren’t exactly stable so they told me that they aren’t ready for a relationship etc. and i agreed that i also wasn’t ready (which was hard to hear but i kind of backed off for a bit because i also am definitely not ready for a relationship).
but the other day i had a shift with them and the whole time they wouldn’t stop speaking to me, they constantly ask if i’m doing ok and then they hugged me when i left and asked me when i was next working and so i told them. that night they also drunk texted me around 3am and i replied the next morning but they haven’t replied since. they also seem really jealous when i talk to other people. 
so anyway i come into work the next day and even though they weren’t working that day, they came down to visit yet barely spoke to me the whole time and kind of made some comments to other people about me not doing my job correctly etc. 
they know about my bpd and other conditions which means that when i’m having an episode they often stay with me and ask if i’m ok etc. but other times when i see them, they act like we don’t know each other and they completely blank me.
i’m literally losing my mind and they’re causing my mental health to get worse and worse but i can’t avoid them because i work with them and i also feel so up and down with emotions depending on how they treat me. 
because they’ve unfortunately become an fp, the idea of never speaking to them again is so terrible to me, yet what they’re doing to me at the moment feels awful too. 

i really need someone else’s opinion because i really don’t know what to do.