Help finding new thought

Hi Brooke
I feel a bit like I should have mastered this part of things by now!
I can’t get behind any new thought about this circumstance in my life.
It’s all related to my usual lifelong problem with feeling like I’m missing out as soon as someone “gets” something I don’t have. Even if it never crossed my mind to want that thing, as soon as they have it, it’s all I want. All my own goals and all the wonderful things I have in my life go right out into the dustbin.
I know intellectually this is a terrible shame.
Right now I am avoiding my own life because of my envy and sadness. I’m not going home, staying in motels, arguing with my boyfriend by text (he’s done nothing wrong)

Here are my models.
C: My friend got pregnant (maybe with triplets – not confirmed but likely)
T: My life will never be as good as hers
F: Resentment, envy, sadness (mostly sadness)
A: Reject everything in my own life – feels pointless now
R: Hate my life, push it away, miss out on it

C: My friend got pregnant
T: ?????? I’m trying: “that’s a wonderful thing” and “I’ll get pregnant too one day” and “We have different lives”
F: (that I want) – peace, love, enthusiasm for my life again
A: be happy when I”m with her, and when I’m not, really into my own life like I usually am
R: relaxed and eager to be with her (instead of dreading seeing her) and really involved in my own life when I’m not with her

Any advice? My core belief is really something like: nothing I have will ever be as good as what XX has; I will never be any good.

I’m also terrified that if I do get pregnant, i won’t love my pregnancy/baby because I’ll always feel in the shadow of her triplets. My sister tells me (she’s a new mum) that really won’t happen but it’s making me wonder if I’m even fit to be a mum.

Thank you