Welcome to Beyond Blue, and well done for reaching out.
I must say that even just from reading your post, and knowing that you are going from someone who was their own boss, and had their own business, to looking at working for someone else. That is a fairly big transition for anyone to make ..... even more so in these trying times.
Perhaps you could consider talking to someone, like a counselor or psychologist, in order to help you process what has happened so far, and to help you develop some better coping skills for the days, weeks and months ahead. Do you think that might help?
Perhaps too you could check out the sites like Seek and My Career, for hints and tips on how to manage the stress of seeking work, and how to handle interviews. I guess that having your own business that you would have been the interviewer for a long time, and not the interviewee, yeah? I know that a change of perspective can be difficult to navigate sometimes, especially when life tends to 'force' it on you.
Anyway, I don't really have too many other words of wisdom to offer. I do hope that helps at least a little?
Take care. I'll be thinking of you. xo