period then positive

So been ttc rainbow baby single mc in April! Anyway came one 28th July normal period 5-6 days long then had a realllly long cycle 46 days! Had a period 12th-16th heavy bleeding as well then stopped and spotted for a day! Anyway did tests during the 46day cycle and all negative. Today cd9 I felt sick and horrible all day and just joined the gym to get in shape went shopping and bought a test as I started spotting again. Lone behold It was possible within seconds! How on earth and what dates do I even go by! My head is all over the place thinking about it 😩.... any help is great full ❤️