How do people deal with the pain?

Broke up a month ago, found out from her as I do work some shifts with her which makes it even harder, that she has been seeing where things go with someone. She said it’s not dates but she has had a coffee and went for a hike and I know she is going for a hike today with him. It caught me off guard it being that quick we where still messaging mainly me initiating and sending Tik toks to each other so i finally just didn’t send anything yesterday and im gonna go in no contact. The pain though that I’m feeling chest tightness, I’m hurting so much. I keep thinking about the what ifs and how together we both seemed perfect for each other. (For context we had been dating for 2 months but talking for about 7 months everyday messaging each other, broke up with me because of feeling overwhelmed, she’s an avoidant and I’m an anxious attachment, I was 5 steps ahead and she couldn’t communicate with me)

But yeah I do want her back I’ll be honest because it was so good but I feel like I have lost her. I just don’t know how to deal with this type of heartbreak as nothing was wrong in the relationship I feel like I have no joy in life and i keep staying in bed on my days off which I know I shouldn’t but my motivation for life isn’t there anymore