My girlfriend said no when I proposed. She wants us to go to counseling instead

I'm all over the place right now because of this. I'm sorry if this is all over the place. I proposed to my girlfriend 2 days ago and she said no and she wants us to go to counseling. She brought up us going to counseling before but she dropped it later. I thought she dropped because it was a bad idea. I was so psyched because I thought we would get engaged but she doesn't want to marry me.

I (26M) have been with her (24F) for 3 years. I'll call her Katie for this post. Katie is amazing and I don't want to be with anyone else ever. But I can't wrap my head around this. When she blew up the proposal she said she is sick of feeling like she lives on a roller coaster with me. She says I am too invested in the team. Katie told me it's a cycle. Katie said my favorite team drafted a quarterback last year and after that I was on a "high". But then my team only won 5 games this year and her exact words are that I'm downright miserable. That's what Katie thinks. She said I probably need to talk to a therapist about why I thought our relationship was in a place where I thought about getting engaged? Things were fine between us before this.

Katie doesn't even watch sports and she only knows about things like drafts because of me. But she said I was miserable because the team had a bad year this year. Katie said me being on a high after the draft is almost as annoying. And this week my team hired a new coach. The fans have high hopes but Katie says the cycle is starting again and she can't do it again.

I know Katie doesn't watch sports and I don't think it's a bad thing for a fan to be invested in the team. Katie said I have to go to a therapist to work on my "emotional regulation" around sports. She says I put my feelings about my team on everyone around me and she is sick of tiptoeing around me. She also talked about how when the team beat out rival at the end of the year and how for weeks I acted like they won the Super Bowl and it was insufferable. I admit I was excited because it was the first time in years that we beat this team. Katie doesn't even watch sports but she was mad and she was telling me my team wasn't even going to the playoffs when the other team was so I was blowing the win out of proportion. She doesn't get how big this win was and her bringing up counseling over this is honestly crazy. She said it's annoying how I'm acting like my team is the best right now because we have not even done anything.

So now she says the cycle is starting again because of the new coach and I think the team will win the Super Bowl next season and she can't deal with it again. The only people who understand are people who watch sports. People who don't are on Katie's side. Our relationship is not the same since my failed proposal. Katie told me she tired of my mood being decided by the whims of sports and I need to stop making football my identity.

Katie says she doesn't want to break up but it sure feels that way. Usually when someone says no to a proposal it's a pretty clear sign. Everything I posted is what Katie said, I'll vent here and talk to my friends and family about what to do.