You feel crap because society try's to tell women that their worth lies in them being fertile and sexually attractive to the majority of men.
I've contributed to the other thread, were the OP thought her friend was ridiculous getting a mortgage in her 40's.
I went through a blip, mainly caused by Peri Menopausal anxiety, but have come through it.
I'm lucky that I have a job I enjoy, so at 46, I'm looking forward to at least 25 years if working life, without juggling child care etc.
Likewise my hobbies are not going to be interrupted, by others.
I no longer give a shit about other peoples opinions, I've been there and got the t shirt, so know when others are talking crap.
I'm secure in my choices, no longer have bouts of confidence issues.
It's taken nearly a year, since my youngest turn 16, to realise that I can do whatever I want, for the first time in my life.
I'm not going to let other people tell me that I can't, because I've been on this planet for a certain time period (or because I'm a certain body size).
Your 40's are liberating, for most women.