I think I am broken!

Marissa
I've had a spotting problem last two going on three months. Month one tested early to be positive and pregnancy did not stay within days of positive, month two not pregnant and month three is 6 days to af and to test but all three months I've had brown mild spotting which I thought to be implantation due to it being week before af but am feeling super defeated. Why am I spotting if I don't end up pregnant. OBGYN said everything looked good and healthy, ultrasound also looked good. What is going on?!?