PLEASE HELP 😭

I'm being really paranoid and dumb rn. So I got my period last month (feb) on the 26th, and it ended on the 5th of march. but I had sex on the 10th and 11th when I went to see My fiancé.my old app said I was ovulating then and I know that youre most likely to conceive a child when you're ovulating. I have an IUD so we didn't use protection and I took a test last week and on Monday, both said I wasn't pregnant. Am I ok...??! Or am I being dumb wtf