Worried

Hi I’m worried so I’ll dive right in…I had unprotected sex October first I started bleeding October eighteenth but like little to no blood so I took a pregnancy test it was negative I went to planned parenthood just in case and to talk about my irregular period and they said that I’m fine that I’m not pregnant I also took another test there it was negative I have taken like 5 pregnancy tests all have been negative I also took the last pregnancy test October twenty fifth the doctor didn’t give much reassurance she just said that when I had sex I wasn’t even ovulating so chances of me being pregnant are little to no chance. I just feel like I did everything I was supposed to do I went to the doctor I took pregnancy tests but I still feel worried nobody explained why my period isn’t normal the doc said it’s normal to have irregular periods once or twice a year but I’m still worried.