I am very worried and unsettled. So let me tell you the whole story.

The first day levi (my boyfriend) introduced me to aj (his best friend) we've all always hung out whenever we have a chance and it's usually a good time. When I first met him I thought he was attractive but I didn't think of him in that way. So more and more over a course of 10 months we got closers as friends. There has been a couple times where aj winked at me, but I didn't take it in a flirty way. But recently I had a dream that me and him were together and had sex. After that everytime I saw him I got butterflies and I feel so guilty about it. I don't like the guy, so why am I feeling like this? Why did I dream of him? And expecially why did I dream of him in THAT WAY??? I don't know what it means and it's kinda freaking me out. I don't want to develop a romantic relationship with him because I love my boyfriend very much. Should I tell him? Or should I let it rest? What if it happens again? Does it mean I like him? Please any answer helps I just want to understand