Hi Fefe
Welcome to pc
Like you had said you didn't do anything close to cheating and for some reason your having uncomfortable feelings about whatever is going on. You had even mentioned it to your b/f so there was nothing "going on" that your b/f didn't know about and you made sure of this by telling. I don't think it's you being uncomfortable about something you did wrong...just you being uncomfortable with something?
Now I'm not sure why you are having these feelings tho when something innocent is going on? Is your mind going further then what is going on in the moment? Even still that's daydreaming and there is nothing wrong with that unless you wanted it to be more or maybe it doesn't really have anything to do with this person you are somewhat flirting with and you aren't having any thoughts like this? I have no idea what's going on here...there are too many guesses I could make as to why I think you might be feeling guilty when I can't see why you would.
I guess what I'm saying is you know best how you're really feeling and what's going with you.
Maybe you have stresses going on in your life etc.?
Anyways...I hope you are feeling better and doing well and again welcome to psych central
~E