Pls help me understand

Alejandra

So I’m just really confused on how DPO works would I start 1DPO on the sixth or the first because my fertile s week started the 30th I know this sounds dumb for me to ask but I’m really concerned because I started feeling certain symptoms and lightly bleeding the eighth but today I bled heavy so I don’t think it’s implantation anymore and that I wanted a baby so bad that I think I’m convincing myself I’m pregnant when I might not be