What do I do? Relationship issue at work?

Long story short: Someone I got along with well at the start has now distanced themselves from me and now dislikes me because of something I did (lets just say I got too carried away with my emotions). We barely interacted now, save for an occasional greeting every now and then (I initiate the greeting). Thankfully, this person is still polite when I acknowledge them, and will say hello back to me, but that’s it. Nothing else happens.

I know I can’t go back as this person has established a firm boundary with me. How do I get over this and let go of not only the guilt and regret, but also the good memories I had with this person. I see this person everyday (coworker), and I’m not sure how to deal with this as I can’t stop thinking about it.

What do I do?