I think any type of anxiety is a by-product of the stress of being in a school environment that isn't a good fit and also possibly the child knowing they're different that other kids. Maybe your DS is 2E and that causes the inconsistences, but the way the testing is being communicated to you isn't very helpful or even professional.
I guess I'd suggest considering starting to work on finding suitable outside testing. My DD's very low processing speed is continuing to be a problem and in this new school, who had all her testing results (but no diagnosis since her strengths are so stong) it's like when I bring it up the words (spoken or written) literally evaporate. It's bizarre, it happened at the last school also. It's like they're scared of it because they don't understand, or just turn their nose up at it.
I'm strongly considering taking her to CTY this winter because other than that I haven't encountered any tester or anyone in her school that seem to understand the 2E concept. If anything it will finally give me some testing results that can made recommendations within a 2E framework.
School is not the best place for these types of kids, honestly. My DD is best suited to live on a farm, work all day, have constant contact with animals and in her free time have a barn full of junk to invent things with. Honestly! But she doesn't so we do our best. Now one of our pets has passed an evaluation for pet therapy so we're signed up to visit a nursing home once a week. My DD steered the whole thing, talking to neighbors with dogs etc. and helping with training. She's very excited.
My short term advice is to find out what your son is good at and just try to soak his non-school hours with things he feels proud of, and if possible things that put him in contact with adults outside school who get him or possibly appreciate him more. It will make him feel better and you also, and give you an alternative lense to see him in, because he needs your support and for you to be his champion.
Also make sure at least one thing that you find for him to do is social. My DD happens to love to sing and she's always successful in a choir/chorus. Musically people always get her, always (but not the teachery kind...the real working, emotional professional types)
We've had tons and tons of failures and I've gotten pretty discouraged sometimes but just had to think of something to try again, reading a new book about misdiagnosis or 2E, trying some other approach.
