Feeling blue about Over the hill 6th month ttc

This is going to be our 6th month ttc now.  I recently found out the previous month I had a chemical pregnancy with no idea until my doctor calls me asking if my period was missed because there was HCG in my blood.  Today I've just been sad and depressed feeling it will never happen.  The cost of trying is ridiculous but not as much as my obsession.  All I think about is having our #3.  I know it may seem selfish to some who have none but it's not with those intentions.  I was a teen mom with my first completely unexpected.  My second I was married but also unexpected.  I've never had the white fairy tale conception date or mutual exciting decision and chance,  and now finally when we are actually ready like really ready and prepared it's not happening.  I am extremely blessed and none the less grateful for what I have but the most thing I value and love is my family.  They are the world to me.  And I would love to share this love with another addition.  I guess it's just not ment to be