WHY do u think u need to be Grateful? After all u say life does not (seem to) offer u that u need or want. I know I won't if I were in this situation.
But u also say "Now I am alone," which seems u DON'T want to be alone. U probably know if one wants something -- cake, sleep, neighbors, trees, you TRY to find how to get these. While you say u are not into crowds, u did not mention you ever wanted CROWD.
But u are "not comfortable in meeting people" so problem is YOUR discomfort about meeting another person. WHY do u think u have NOTHING that another PERSON might find interesting, even enjoyable -- especially given the incredibly tough life you had while growing AND having lived enjoyable life in marriage of 6 decades?
I think u are starting from a preconceived notion that people will not WANT u to connect, even though I see NO reason for u to feel this way, indeed opposite! IF someone seems Not Interesting enough, Move On, life is too limited to be wasted where u can't have a MUTUALLY rewarding experience a key point in ANY true friendship, even a good acquaintance.
BTW my current nearly full-time 'occupation' is to find a 'friend whom u can at least carry on interesting experience in at least ONE area of interest that YOU BOTH care about (game, sport, hobby, political economic spiritual or social issues) I don't expect more -- if we click on more than One area, great, but it's NOT a necessity.
I hope u go out looking for THIS kind of connection where BOTH of you will benefit. By YOU not doing it, YOU are also depriving the other of a possible rewarding encounter. That's what's so noble about Friendship is!
Good luck to you from a fellow man who is in the Octogenarian decade.