[DeletedAccount53]

I'm sorry this has happened, making you feel confused, yet it is quite normal to be crushing on her, even as she is straight.

However, maybe your co-worker is unaware of what she's doing to you, so I suggest that you should leave her to make the next move. If she continues flirting, then as coolly as you can, ask why she's being clearly interested in you as it's obvious she asked you to her own gym that is several miles away. I'd be concerned and questioning, too.

Depending on her answer, ie. if she says she's questioning her sexuality, or, that her relationship is floundering, then I feel you'd best set a boundary with her because your feelings for her is affecting your everyday life.

It's a difficult situation. But much depends on why your co-worker is acting this way. If I was in your situation, I'd get straight to the point and ask her. In my dealings with people, I'm straight down the line and always have been. This way, at least you will know, Sarah, rather than continue being in emotional agony.