So the Dialectal Behavior Therapy (DBT) skill above is called sensory-self-soothe, but it sounds like you might need something more like opposite action. I do recommend you take a breather first, so try to take a little bit of time away from those things entirely. This is to let some of your overall emotional inflammation die back before actually getting to work on this. You’re not gonna get this done right if your emotions haven’t even had a chance to stop getting their ass beat. How much time is gonna depend a lot on how you specifically relate to or need any of those things, but even 15 minutes can make a huge difference, especially if adrenaline/panic juice is involved. That said, if it’s some distant acquaintance you might just cancel lunch and get back to them next week, y’know?

So opposite action means intentionally acting differently than the emotion you are feeling calls you to, with the eventual goal of changing the emotion you are feeling. The worst part is that that’s a legit measurable phenomenon in behavioral psychology; you actually can fake an emotion until you feel it. Your brain will literally be like,“well. I’m smiling. So I guess I’m happy???” Brains are dumb but the cool part is once you know your own exploits stuff gets a lot easier, and this one is in pretty much all human brains.

IMPORTANT FIRST STEP. should you be using opposite action to solve this issue? There’s a decent chance that whatever feeling you’re having is actually relevant, actionable, and important, so you need to rule that out before you use it. If there is a person or entity who is physically hurting you, constantly criticizing you or saying hurtful things, controlling you, etc, you’re supposed to feel anxious/generally bad around them or it. Those unpleasant emotions are there to tell you to move away from something dangerous. I don’t know enough about your situation to know if it’s legit or not, I have no way of finding out over an internet message board, and more importantly, it sounds like you’re talking about multiple things, so I suspect it’s a mix of both legitimate and trivial anxieties. You’ll need to evaluate the relevance, importance, and action-ability of each emotional state on a case by case basis. If one of them doesn’t match up, opposite action is probably the wrong skill. For reference:

• Relevance - “is it an emotion that makes sense for me to feel about this situation?” If not, try to figure out what you’re actually upset about first.
• Importance - “do I need to act on this?” - major fight with your significant other? Yes. Some idiot took too long in the crosswalk? No. If it is something important, you probably either need
  • one of the problem-solving skills like pro and con lists to differentiate options or behavioral chain analysis to break down specific, individual undesired behaviors (often but not always substance related).
  • one of the interpersonal skills, specifically DEAR MAN (negotiation) or FAST (negotiation / boundary setting).
• Action-ability - “is there anything I can do about it anyway?” If you are in an abusive / oppressive situation, sometimes it’s ok to push your emotions down for a bit for the sake of safety, just also try to focus equal energy on finding safe outlets.

How to use it? idfk lol I’m not in your fucking brain and we’re probably not even in the same country. Be willing to be a little creative though. A great first step is before you even go back to trying to interact with that person or thing, try to spend some time reminiscing about what you did like about that person. Scrapbooks and photo albums are great for this, physical or digital. Video is extra good. Do an activity you bonded over. Use, wear, look at, or otherwise enjoy a gift they gave you. Read a nice message they sent you. Protip: start collecting stuff like this about your loved ones in an accessible location if this is a problem you have often. When you’re with the person, the two big things I recommend are:

• keeping your posture as relaxed as you can. I don’t know if you’ve ever learned to swim or a sport or craft where you have to relax your body but that’s part of it. The other part is to think about how you interact with an overall space when you’re comfortable. How do you sit on a couch when you’re comfortable vs uncomfortable? How do you walk down a hall? What clothes do you wear? What are your mannerisms? Study your comfortable self like an actor doing a character study, then practice playing that part (as much as is appropriate anyway, some comfort behaviors are for private environments only obviously). It will legitimately feedback and make you less anxious.
• doing favors / generally being kind to the person. This mostly speaks for itself, but to illustrate my point I’d like to point out that it’s also a known behavioral psychology phenomenon that successfully getting another person to perform favors for you will legit make them like you more.

Like I said, dumb, but very useful once you know the exploits.