“This is getting serious” and panic attacks

I wrote in before about being afraid that my boyfriend and I are getting serious. I think I am afraid because I’m thinking it will be embarrassing and humiliating if we don’t work out. Because I can’t ever keep a relationship going. I always end my relationships.

C: my relationship
T: I always end my relationships
F: self-pity
A: sabotage myself, look for evidence to end it, worry he’s thinking of ending it,
R: I end my relationships or the very least create disconnection

C: my relationship
T: this time will be different
F: empowered
A: take responsibility, coach myself, choose deliberately,
R: I make it different this time

The other thing I want help with is that I’ve started having panic attacks again. I think I am sabotaging myself with these too. It’s like being pulled backwards towards a result I don’t want. This is embarrassing

C: going somewhere in a car with people
T: I will get diarrhea and then I will be unworthy
F: anxiety
A: worry, avoid the circumstances, beat myself up for avoiding and being unable to control my thoughts and my body, look for a toilet, imagine having to go on the side of the road, anxiety worsens, diarrhea, nausea,
R: I create the situation I fear. I reject and abandon myself. I have diahrea lol

How do I deal with this? I think part of the problem is I’m resisting it all soooo much. I am really unwilling for this to happen. But it does happen so I guess resisting it does nothing.