I'm so stupid!

I keep getting flashbacks of my ex bf and mines conversations. He said " I love you " but it was just the first day. I think he just wanted to make his ex jealous. His ex was a really close friend that i had. And I said " I love you too" I didn't really like him. But it just makes me uncomfortable thinking of our conversations. We only dated for like 2 days. I broke up with him so I wouldn't hurt my friend (his ex) but she said she didn't care. Me and her stopped being friends after a few months.