Been there, done that. Not an Oxbridge graduate but come from a country where a much better lifestyle is affordable on a more humble job, also parents who perhaps naively thought that a good PhD with favourable reviews of thesis meant I would walk into a high-flying job. Even more so as younger sibling did that very thing.
Instead dh and I had to make a very limited income do, disabled child but no DLA (fluctuating disability), myself suffering from anxiety which made it difficult to put myself forward.
But looking back, in my late 50s, I look at these things a bit differently. I may not have lived younger sibling's life, but I've lived my own- and if I may say so I've been bloody good at it! 
I may never get that invite to chair a funding committee for any country's equivalent of the British Academy or get invited to be a guest lecturer on another continent, but if tough times come, I am absolutely the one that can keep rustling up new and interesting meals from a bag of potatoes and some lentils. I am the one that kept my family going during the other bad times, the one that made them believe you can walk on water, the one that still to this day gives dd the courage she needs to battle on despite her disability and pain.
Spoke to younger sibling on the phone the other night, the one who has done all those other wonderful things, and the conversation was punctuated by sighs- his, not mine. For the first time in his life, what with the pandemic and the possibility of economic recession in his son's field, he is having to face the prospect of uncertainty and there's been nothing in his life that's prepared him for this. Dh and I otoh...
I did feel bad earlier this year: after many years as a carer and part-timer/occasional free lancer, I had finally managed to crawl back to a point in my career where I was offered a full time contract at a reasonable level. Students liked me, work was fascinating, my research contribution got top ranking, and for the first time we had money to spare. It lasted a year- then came the pandemic and my contract was pulled. Not saying that didn't hurt. But it wasn't the fear I heard in my sibling's voice. More of a "oh well, here we go again". And that was, in its own way, quite reassuring.
Hang in there, OP, you can do it! It's not as glamorous as a high-flying career. But it's worth doing.