Never understood why one should feel better knowing that someone else is in an even worse situation than oneself. Makes me feel sorry for them also.
I'm unsure about lifetime truths, but maybe try to look at it this way. In the past you did what you wanted to do and you succeeded. But life is full of change and now take the time you need to find new goals, new interests.
Of course it may take a while while you mourn for your previous situation, but the future is simply waiting for you to build it, and you have a free hand for that, more or less.
Consider what else you have been interested in but not got around to. Or what else you might like to take an interest in.
It sounds to me as if you neglected maintaining a group of friends in the past, relying on family. So, when you do think of an interest you might like, try to join a local group of other interested folk in order to make human contact and hopefully friends there. (Obviously after this present lockdown.)
Maybe, since you seem to be a caring person, consider volunteering for some charitable work. That also allows you to meet folk and get you out of the house.
Then there's other classes. Ever wanted to sing or dance ? How about hobbies, would you like to cook, or make wine/beer ? How about taking up painting, or tapestry. Do you have a garden, you can chat over the garden wall to your neighbours about how it's going. Maybe learn to play a musical instrument (I understand neighbours love it if you learn the violin or the drums).
IMO it's about getting more relationships into your life, and finding those goals you can strive for, giving meaning to everything. Each individual differs as to the exact path, you should spend a little time planning yours, and maybe try to limit the time analysing what your life used to be.
Take time to feel down about those who are no longer in contact with you, but know when you feel x minutes is enough for now, and that you are going to find something else to concentrate on. Only you can decide the right balance.
Good luck with the transition. Remember nothing stays the same forever, so during times when you are down, it means you will be up a little later.