6 weeks pp

I had sex 3 weeks after I gave birth once then a week ago again twice . I guess they are right after you have a baby your hormones are crazy because I never been this horny ever . 
my question anyone been through this got pregnant right after is it possible this early ??? I took a pregnancy test today around 8pm I been having pelvic pain and sharp pack pain also kinda nauseous n constipated could it be a  new pregnancy.