Getting very depressed now

I am a mother of one. My son was born 2012. I haven't took any form of birth control since then as I do want more children. My partner didn't want to try for another until our son reached 2 though so we used pull out and rhythm method. My son turned 4 in Feb, so we have now been trying for over 2 years. My periods are pretty regular, I do ovulation tests so know I am ovulating, yet still no pregnancy. I have put on 3 stone since having my son, which I am losing very slowly. I am too scared to go the Doctor incase he gives me bad news. I am currently 6 days late, but 10 tests have all come up negative so now I'm wondering where is my period 😔 Any thoughts? Thanks xx