Scared im already pregnant again??

Katie
So my baby is almost 6 months old and i had normal periods after she was born untill this month. Im now 19 days late and freaking out... ive only had sex 2 times and we used a condom once and he pulled out with the condom, second time he never even ejaculated. So if im pregnant it would have been from precum litterally him going in once before the condom was put on im sorry this is tmi just trying to be specific. Anyways ive taken 3 dollar store tests and 2 clear blue tests and all are negative not even a slight trace of a positive line. No pregnancy or period symtoms and im honestly freaking out. I do not want to be pregnant again. Can you go from normal pp periods to irregular like that? And before anyone says a blood test i do not have insurance so i cannot go to a dr and get any testing done. Please let me know if this has happened to you as well.