Thought menstrual cup was secure but still leaked?

It's day 3 of me using this Diva cup. Day and night one: great. No pain and no leakage. Last night, however, I leaked a lot 😒 and it was hard to get the cup out. I know your cervix goes up and down during your period but gosh. It was a struggle. Anyway, what's a sure way to prevent leakage? Push it up more? Pull it down? I feel around the rim. Maybe I just wasn't thorough enough?