<human>: You'd think I'd be past this sort of thing, but I guess not. I don't quite remember how it started. We've worked together for the last ~5 years, and we hang out with the same people and end up drinking together a lot. Well, a few months ago we ended our evening with a fairly hot kiss that would have gone further had the moment allowed it.  Last night we were both a bit tipsy and she drew me a heart and said "I love you!". It wasn't exactly a romantic moment, it was phrased more like a sarcastic "ha ha you so funny" kind of thing.  But...she drew me a heart while she was saying it. And said it twice to be sure I heard her.

I don't remember how I reacted, but I know I didn't say it back cause that's a big statement and I got the impression that it wasn't the casual banter she made it out to be. But I do like her, a lot. So I don't know where to go.  The rest of the evening went well, she didn't seem hurt or anything, so maybe I'm being paranoid? So I guess two questions: 

* That casual "I love you" wasn't that casual, was it? Or was it? I hate mixed signals.
* How do I say "I heard you, and holy crap that was hot & made me giddy, but I'm not quite ready to say it back"?

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: She said she loves me, and I'm not creeped out or anything, but I don't quite know how to respond.