2nd month postpartum period ?

Hi everyone . I had my daughter 2 months ago . I already had my first postpartum period & now this month I was cramping 2 days ago as if a period was coming so I prepared myself I put on a pad & waited but no period . My breast are slightly sore & I fear I may be pregnant again . I took a test yesterday it came out negative . Anyone else experience this ? I'm not breast feeding btw