Im sorry you are feeling this way.
Can you go back to the company and advise that you have now reconsidered and want the role?
Im sorry your anxiety is heightened have you ever seeked professional help for your anxiety?
Its not too late for you, good things will still come your way.
Have you ever really been able to set goals that you really want to achieve?
It sometimes takes a little time to really know who we are as a person and what we really want to achieve in our lives.. sometimes this happens later in life..
When in comes to marriage I know of people who met in their early 30 s and are married now with kids… your time will come.
What is meant for you will always find it’s way to you.