Should I tell her?

There's a girl at my work who, a few months back when I was questioning my sexuality, I fell for. Or I think I did. She's pretty, funny, sweet, thoughtful, caring, and we've loads of common interests. She's a "tomboy on the inside" and is GORGEOUS! There was a day I wanted to kiss her so badly, like a rush that was really hard to control.
She's straight, AND Catholic - recently so, but she upholds a lot of their values and although she's nothing against homosexuality, she doesn't have much against anti-gay Catholic values simply because they're "traditional". Well, when I say "doesn't have much against", it's more a reluctance to say, "actually, maybe the Church should be more open". I'd walk into work and she'd be there and I'd just light up, it was lovely but also scary. There was a time over the summer (and it happens from time to time still... well, a fair bit) when the idea of having a relationship with a man terrified me and made me feel sick and scared, and when it'd get really bad I couldn't help notice her, and felt so... in the moment but lost, alone, ashamed. I'm not sure if the feelings are still there - I've been straight/gay/straight/gay and when I felt "straight" I just saw her as an awesome friend, but now I know I'm gay, should I tell her how I felt?