Mirena iud

Okay so I have some questions lol.

** please no rude comments **

I’ve had my iud since I had my son in 2018 and I haven’t had sex in about a year and a half..

( I know its been forever I went thru a really bad break up and didn’t want to jump right in bed with someone else ) well my Periods have been regular since I’ve had my iud & I had sex on September 8th and still haven’t had my period this month . I went to my ob’s office and had a blood pregnancy test Monday and it came out negative. But I’m still panicking since i haven’t had my period this month.. what would you do ? Would you panic? My dr said there’s nothing to worry about & that it’s normal to just stop having your period with mirena , but It’s freaking me out that I literally miss my period after I have sex 🤦🏻‍♀️