Girl sends me mixed signals. What does it mean?

Ok there's this girl at my job that I'm attracted to. She's beautiful. She has a boyfriend who she has a kid with and has been with for a while. But from the one time she mentioned him to me she spoke as if they weren't together. she hasn't told me that she's with him and doesn't know that I know from someone else. I've heard that he cheats on her and tried to get with one of her co-workers at a gathering outside of work. She doesn't really mention him to me when we talk.

Every time we have the opportunity to work together at work we have amazing conversations. In conversation, the eye contact is strong, a lot of smiling and laughing, conversation lasts long time flies, I give her compliments and she receives them well. When walking pass I catch her looking at me. And sometimes when we talk I think she gives me "the eyes". I can't quite explain it but it's a vibe I get from her gaze.

But sometimes right after we have good days where we get closer she acts like she hates me. She becomes distant. She gives me attitude. And we'll stop talking for a while. Then a couple days later she's back to being social and joking with me and acting as if nothing happened. I ask her why does she act mad with me and is there a problem she says "She's not mad with me and that she acts the same everyday." But it's obvious she was acting different towards me. This cycle has happened a couple times.

I'm kind of confused about her inconsistent behavior. I have a few possible reasons on why it could be. One is bc there is a lot of gossiping that goes on around my name at the job. A lot of ppl don't like me there and throws dirt on my name. My reputation there is that I'm a player. (But I'm social with everyone at work. Maybe she saw me conversing & laughing with another female co-worker and took it as flirting.) Also she is close friends with a girl co-worker who is friends with her boyfriend and with my ex. but at one point this co-worker liked me, before I started working there, and I think she may be jealous of how close we've become. So she may be encouraging her not to talk to me. Or it can be that her boyfriend heard something from the "mutual friend" about how close we are at work and has argued with her about it. Or is she just playing hard to get? I don't know.

I'd like some opinions on if you think this girl likes me or not? What could be the cause of her behavior? What should I look for as hints on how she truly feels about me?