What could it be ??

So I officially missed my period when I was 1 day late I lightly spotted brown then light pink a day later (not enough to wear a panty liner or a pad) I felt cramping like my period was coming but it just never did now my breast ache here and there and I’ve been nauseous but not throwing up no period, no more spotting and no cramps anymore what is going on any ideas ?? Comment please