Implant bleeding?

So I miscarried for the second time last month, my husband and I haven’t been actively trying again, and it takes normally a few months for us to fall pregnant but on Wednesday I thought my period had started but it only was spotting which lasted until last night and it hasn’t continued at all today. I’m not sure if it was implant bleeding. I’ve been tracking my bbt with my Apple Watch and it hasn’t been up like it was when I was pregnant last time.. but I also know it’s been 9 days since I think I potentially ovulated. I’ve taken some pregnancy tests and they have been negative.. I’m just confused.. I’ve heard that you are more fertile for the first 3 months after a miscarriage. But yeah I don’t know.. and advice or ideas.