I need to know im not mad

Hi all im not sure how this works so will just lay it out there.
Im 30yo married with 3 gorgeous kiddies-my eldest is 10(boy) then a 5 yo boy and a 3 yo lg.
I am extremely happy in my life and i was blessed with 3 very healthy kids but lately ive had this nagging in my heart,my brain,my entire soul that I REALLY want another child. Im sure im NUTS!!!
while all this was going on my hubby and i had an oops 1 dbo. At the back of my mind i was hoping and praying that this would get me pregnant as my last pregnancy happened the same way, i couldn't wait to do a test and gave in 6dpo--obvious negative result
I am now 11dpo and most of the symptoms i had have subsided-af is due in 2/3 days and i cant help but be upset at the idea.
Im making myself truly crazy with all the what ifs so i basically want to know if anyone else has fallen pregnant after just one try and after getting an initial negative on a hpt????