No af but bfn hpt! Only few symptoms but not as many as the last pregnancy?!

Right so on 10/12/2017 (December) I had a miscarriage 4 weeks later I’m having really bad back pains, headaches, dizziness (the usual for me sometimes anyway) bit of blood taste in my mouth? But still bfn?!

During having my miscarriage my pregnancy test came back negative 6 hours before it ended?

Am I thinking too much into this or could I be expecting again because there’s nothing more wanting this baby? Because last pregnancy I missed my period 4 days and the hpt was a bfn but 9 days later it was a bfp! I’m only a day late?!

Confused!