Bfn 18 dpo, light period and tinge pelvic pain?

Hi all

I am still wondering if its possible to be pregnant. I chart my period and symptoms on a app and had spotting on march 24 and 25 pink and brown with lots of symptoms I never get. I had lower back pain tender heavy breasts cramping and headaches. On the 26th I had the same symptoms and started what I think was my period. It lasted 5 days with the same symptoms everyday. I tested twice and got 2 bfn. I now have stopped all symptoms except for cramping in my lower stomach and sharp tinge pain. Could I be pregnant?