is my best friend jealous?

so my bsf has recently been telling me she doesn’t like my bf and explaining why. he’s insecure and definitely has some stuff to work on. She is generally really insecure and i feel she is judgemental to others like even our other friends. she has said she’s annoyed by him before and how i can do so much better and now she’s saying i should leave him or just look around but not cheat. and now i know this is dumb but I’ve been stressing that she’s gonna leave me because of this. i had a toxic friend in the past she almost left me for but instead talked it out. i don’t really have any other close friends so I’m just scared and i hate how pathetic that sounds. but yea, she’s been telling me to leave him and stuff and she’s never had a bf before so I’m wondering if she’s jealous. But i don’t know. what should i do? I’m stressing