Advice please

I'm needing advice two days ago I started cramping in my back and lower right pelvic area my last lmp was 4-20 still have yet to get it I thought maybe it was coming on starting yesterday I was nauseas on and off through the day more so in the morning time and same thing this morning I've tested with negatives and I would be 4 weeks if I conceived so am I testing negative cause I'm just not pregnant or is it kinda too early still? Thanks!