Am I pregnant?

according to my period tracker i started four days earlier than i was supposed to. in the first few hours i had intense cramps and a heavy flow of blood and my nipples have been sore for a few days. i read that implantation bleeding is usually a light flow but could it be IB or just a normal period? i'm just waiting to see if it'll last more than two days 😪 also can i take a pregnancy test while i'm bleeding?