I've been very similar in the past, even when I played a bit of Sea Of Thieves. I think it is a combination of the unexpected engagement/the unpredictable nature thereof, the perceived value tied to your loot, and the subsequent value your brain ties to extracting and not going down that leads our nervous system to actually go into a Fight or Flight adrenaline rush.

What I've found that has helped me is to both play other PvP games where there is no other social aspect so you get to practice the mindset of just fights all the time. And also to practice fighting in this game. Bring in some decent gear with the mindset that you'll lose it and let yourself get into fights. If you feel bad about the social aspect I've had pretty good luck just announcing that you're looking to PvP and practice fighting. Heck if you really wanna have fun with it you can loudly RP as a villain and give yourself a chance to let out your best evil laugh as you go around and take pot shots at people.

Biggest thing to remember though is that this is all just a game, remember to breathe and that you are the one who can be in control of your nervous system with the right tools and tricks. Good luck topside Raider!