First month using opks need help please

These are my opks I've been testing twice a week for the past week I'm almost certain I ovulated yesterday due to very bad cramps and cm the last 2 test is from this morning is it normal for them to go negative so fast when I had positives for 2 days before and should i stop testing now and enter the dreading tww also since im sure I ovulated yesterday is today classed as 1dpo sorry for all the questions just want to get it right :-)