has this ever happened to you?

My aunt was pregnant with her oldest and it took her a while to get a positive pregnancy test. With my first pregnancy I was 10 weeks when I finally got my first positive pregnancy test. Im trying again two years ago I miscarried at 12 weeks. Just recently I was diagnosed with a severe case of hypothyroidism ( I was passing out because of it) and I was having regular cycles but I started taking my meds my cycle is late so if I am ill be 6 weeks so im playing the waiting game I have tested it was bfn (big fat negative). So my question is has any of this happened to you? If so any advice?