might be pregnant

okay so a few weeks ago i thought i was pregnant but then i got my period at the expected time, except this time it was different, there was blood but it wasnt a normal period, it was more like spotting. and today out of nowhere i feel super nauseas and want to throw up! i took a pregnancy test from the dollar store before i got my “period” and it said negative, so should i get checked? is it possible that i could be pregnant ?