Did you really do everything you could have done?
Did you really give it all you've got?
And did you do it for more than just a few months?
Did you do things you've never done before just to make it work?
Did you try to learn new skills?
Meet new people?
Get new insights?
Read books about it?
Did you do things that made you feel very uncomfortable?
That are outside your comfort zone?
Did you do a lot more than you had to do?
For a lot longer than most people ever would?
If you've answered "yes" to all of the above and it still doesn't work, then you might want to consider it.
You might also want to consider it if you think that none of the above is necessary...