IMPORTANT HELP

Sooo I’m 17. I recently just had a baby boy 11/25/2019. I am worried that I may be pregnant again!? I remember my fathers child said he think he may have accidentally ejaculated in me February 29. I had old birth control pills and took 3 then started bleeding the next week (started my period early) then the next month (April) I had 2 very short periods 2 weeks apart. And now in MAY I haven’t gotten my period !????? I took a test like 2 weeks ago it was negative?