This is my first post,I’m not the type to write on things like this,I just need advice.I am 17 and I really need help,me and my bf have been together for 1 year and 8 months,at the start of the relationship,I wasn’t jealous at all,I got the bar and everything changed,I feel that my mental health has gone so bad and I have become a really jealous and possessive gf,I hate it,it’s so bad like to the point where anything with girls will make me so angry or upset.For example anything from movies with girls or a girl on the street to a photo of a girl,everything makes me annoyed like I don’t even like watching films with attractive women in with him as I overthink everything and just think that he will be turned on and attracted to them more than me,Ik it all stems from insecurities and Ik it’s stupid and he always reassures me that he loves me and thinks I’m the most attractive girl ever and he’s honestly amazing but I can’t seem to get over it,there’s so many films that I want to watch and I’m just hurting myself but I can’t get over it.I literally feel like a psycho and I want to change but I don’t know how to stop these feelings,Ik I’m just overthinking everything and I’m aware I need to change which is the first step but I don’t know how.Its so bad like if he mentions any girls no matter what’s it about,I get so jealous and it’s so stupid.I just can’t help it like say we were walking down the street and a girl was wearing a sexual outfit or cleavage out walking past ,I would instantly go in a mood thinking about did he see etc and it’s all starting to affect our relationship so I would really appreciate it if anyone knows what I can do to become less jealous.I am also curious to if anything has or is going through anything similar to me. Sorry for the grammar mistakes.