Confused

Hi :) I just started using the ovulation kits with the pregnancy tests from earlypregnancytests.com and yesterday I was supposed to start but did not I took a pg test negative so being curious I took an ovulation test. The test had two dark lines matching meaning surge of ovulation right? I thought that meant you have 24-36 hours of ovulation but when I took a second ovulation test this morning the second line was lighter? Does that mean I missed my window? And is it normal to ovulate when your expecting your period?