Could I be pregnant but the test doesn’t show yet?

𝓚𝓪𝓻𝓸 𝓐.

My period has been 7 days late so far

Been feeling a bit dizzy and nauseous these days

Took a pregnancy test on the 17th march which came out negative and another one this morning again negative

Haven’t been experiencing any signs of upcoming period

My breasts have been quite swollen and sore and some pain in my lower back

Feeling a bit confused on what could be going on?

Could I be pregnant but the test doesn’t show yet?