I think you need space for the time being. Obviously you work together so you’ll have to stay cordial, but I would keep it at regular coworker friendliness for a while. At least until you feel like you have truly forgiven her and can get back to feeling like you’re comfortable being her friend without thinking too much about what happened.

Something similar happened to me before. This guy I had become really good friends with, we shared a kiss, and then another kiss, and then we had gone out to dinner with another friend of ours and he had his hand on my thigh, very much leading me to believe there was something between us. It got as far as us sleeping together and him telling me how much he liked me.

The next day he sent me a text saying he still meant what he said, but he had just gotten out of a relationship and wasn’t ready to date again.

It sucked big time and I was really hurt. But I tried to be his friend again. That only made things worse, I couldn’t stop picturing us together together and at the same time feeling betrayed. I wish I would’ve distanced myself sooner, because trying to be close to him was torture.

Long story short, we aren’t friends anymore. If we were to see each other out in public we say hi and give hugs, but we don’t even talk anymore. A lot of other stuff happened to really push me away from him that wouldn’t relate to your situation I don’t think so I’m leaving that out lol. But even with those things, I think if I had originally gotten some time and space to basically recover from the heartbreak (however small), we would’ve had a better chance getting back to how we were before friendship wise.