Chemical pregnancy


Confusing between late period or chemical pregnancy???as what i'v search and i am experiencing right it similar looks like chemical pregnancy after 13 days miss period and got postive line ang april 28 then got faint line and may 1 then may 2 after got my bleeding heavy..what also im confusing now? How long bleeding will last? If you got chemical pregnancy loss??? Me only 4 days? Some one can answer please??.