Period is late but have t had sex! Help

Ashley

Just had a baby in December! My period came back in March(normal), has sex at the end of the month with my husband, 9 days later got me period for April l(normal) and now may according to my app I’m 4 days later. I haven’t had sex since last of March. Can I still be pregnant??

Maybe it’s just late.

I took a test 2 days later and it was negative