weird searches on macbook

ive had my macbook air for about 3 years now. about a year ago i was entering my email to a website to sign in and it suggested a random mans email underneath my own autofill. thought it was a bit strange but ignored it. and now tonight i was on my universities online library. i clicked on their search bar on the website itself and it came up with some things ive searched myself, and a few things i most definitely havent! one search was the area i live in, two were explicit and one was literally "poster". could i have been hacked or could someone be syced to my laptop? it never leaves the house, is not used by anyone else and i dont search those things aha. any advice would be greatly appreciated thank you