Oh dear, I'm sorry you were upset. It's easy for me to suggest things Beckett and probably not so easy for you to do.
But here goes:
Plan for the future so lunches at holidays times are not so solitary. Have a friend round for the day. They may be just as lonely as you.
In fact there are many agencies who may be able to steer you towards people who would deeply value company at this time.
If you are a member of clubs, there will probably be other widows who would be glad to share a meal. Or go out somewhere together.
Does all this sound trite? I have to confess I am never lonely (I'm a widow) so these idea may be useless.
But I AM thinking of you and hoping you feel much better by the time you read this.
Is there such a thing as delicious ready meals?