I feel soooo worn out and alone. What can I do to improve my non-existent life?

Honestly, there is a great need of senior caregiving for stay at home low income status folks. The minimum wage is available hourly & paid by the state. Each client would apply for tasks to be assisted with based upon their actual needs & they could vary from garden care to grocery shopping or light duty housekeeping. You could gain some income while keeping as busy or not so busy for another person who is less agile. Often times, trying out a new hobby like playing an instrument or photography, writing poetry, bird watching or bowling helps with the social needs. I have found that keeping busy helping others after someone close has passed away is beneficial for everyone. Family & friends who are married & do not caregive just won't always understand what kind of solitude you are dealing with.

Honestly, it sounds like you are experiencing some depression. Have you considered speaking with a therapist for ways to forge ahead.

I totally agree with Alva, ditch your family if they aren’t going to be close. Or how about, accepting them for who they are and not allowing them to cripple you from moving forward. Sure, in an ideal world, everyone would have a loving and supportive family with similar values in common. That isn’t always the case.

Work with a therapist to concentrate on YOU and healing any past issues, in order to progress to a better place in your life.

Plus, you never know how things will end up with your siblings down the road, but If you and your siblings remain going in separate directions, so be it. Take control of your own life.

Take baby steps. Nothing is solved overnight. It takes time to build a life that you will be content and productive.

Maybe volunteer somewhere and make friends. Or take a class and make friends.

Being single and child free, you were probably "selected" to care for your mom by dint of your "FREE" status. Your brothers probably presumed because you are "a girl" with "no family" that your life was the easiest to offer for sacrifice. I have no doubt you loved your mom and she loved you, but caregiving sort of leaves you in a lurch after the person you cared for dies. And even if your brothers had participated in care, they go back to their other interests while you are left to pick up pieces with no one to even inquire about you. I get it. It's called singlism. Just listen to politicians....they go on and on about "families and kids" but NEVER spare a word about the single population whose efforts go unnoticed and unrepaid. With that: Notice yourself!! Take yourself out to lunch. Treat yourself to a massage. I know that it will difficult on a single person's retirement stipend (yes, housing costs just as much if you are single or coupled, but in the case of a single, we pay for it out of one income instead of two). Try to take the time to enjoy what you have and be grateful that you don't have to care for an aging spouse or snot-nosed brat! :)

I jumped past your first question, and didn't realize that your Mom has passed already, so my initial response was all wrong. Relative are there by blood only. In my opinion, if they are not quality people, sweep them on our of your life and make good friends that bring you joy.
Thanks RealyReal and cxMoody for letting me know I need to slow down and read or get a head-exam, whichever comes first. You caught me when I could still edit. How good is THAT?