As long as you din't have any condom failures, like tears, holes or rips, you're fine and not pregnant.
If you're using your phone app to let you know when you're ovulating I wouldn't count on that. Not all women ovulate in the middle of their cycles. The only way to know for sure when you do is to use an ovulation kit for several months.
The reason I'm telling you this is because I don't want you to think it's your safe time and not use a condom. Use one every single time and make sure there are no tears or anything like that after intercourse.