Maybe it could something where you could be deficient in something? Vitamin D and B12 have muscle weakness and short of breath

Uhg I've had that happen before. I had bad sinuses/asthma flares (even my eye has something I can't figure out) and the doctor just kept giving me random prescriptions and not really trying. I hope you can figure it out!

I’ll get anxious and sometimes feel like I can’t think straight throughout the day. Fucking up at work and everything. I get muscle weakness but it’s from my hypothyroidism.

I also have trouble standing for long, recently I noticed that when i’m standing it feels like someone is sitting on my chest which is a new anxiety symptom of mine

You are not alone! I get this way when I am on the verge of a panic attack, the only thing that helps me is laying down,and it instantly stops the feeling. Unfortunately that isn't something you can do always, like say at work, but I haven't been working due to my anxiety. I know how awful it feels and I really hope you find some relief asap. 💞

I do this too. Every time I get really anxious I think I tense or something because after a little while it feels like I'm going to collapse. I can barely even walk. Make sure you are eating too, though. That's something I do that doesn't help, is forget to eat because I'm anxious and so I'm slightly nauseous. But after I eat I'm not quite as weak

I have experienced this actually! It typically happens when im at the grocery store since its a huge anxiety trigger for me! I tend to try and distract my self such as listening to music and daydreaming.