Worried

So almost a month ago ( February 24th ) I took a plan B and my periods normally last 4 days . In February my period came the 16th -19th . After I took a plan B on the 24th I experienced a 3 days of bleeding on March 3rd through 5 . Which was unexpected because I just had my period. I was reading about the symptoms of plan B’s and saw you can have a little bleeding from it . It’s March and I haven’t gotten my period yet , I’m 6 days late on my period, I’m also not pre cramping like your supposed to when your cycle is coming . Im experiencing Tender swollen breast , bad back pains , swollen feet , fatigue , frequent urinating as well . Because I’m 6 days late my boyfriend and I decided to get a clear blue pregnancy test this morning and it said “Not pregnant” but these symptoms I’m having aren’t adding up to me , was it too early to take that test ? I’m very confused ..