Period late

Little

I have spotting last moth from 19to 22 it's not cycle because my cycle is always 26/27 date in month it's like clock in time there.

I have done 2 tests cause i think i'm preg, went to doctor and he told me to wait. Now it's again spotting light, not heavy, brownish just trace on underwear, sore breasts and backpain... Could i be preg after 16 days late period and 2 negative tests? Any experiences?