You won't feel this way forever. Panic attacks and awful things but it is your body, you can find way to get it to work with, rather than against you.
Starting a new job always triggers my physical anxiety even if mentally I am pleased with the job. Here's a list of things that help me in the moment.
Counting, not just a little, I'm mean proper counting, slowly until you feel stronger. If you're not alone, and need to appear to be working/listening this is a good one. You can also count objects if you like. Number of keys in your keyboard? Number of lights in the office?
Set your self a time to worry, it sounds odd but for me it buys me time. So if I know that at 6 I am allowed to worry for20 minutes (set an alarm) my brain seems to feel safer, a bit like it knows it will have time to be heard. In the allotted time don't fight the thoughts or physical reactions, just sort of observe them.
If you can, break things up into small slots. I read somewhere 'A person can tolerate almost anything for 15 minutes' and it stuck with me. Usually when I get to the end, I find I can do another 15. Then another.
Write down a list of things to be proud of and keep it in you. Ideally use paper and not a screen. I have a small list folded up and kept in the back of my phone case. Get it out and read it when your having a day that might be triggering. Mine said things like 'You beat 50 other applications to be here - that's damn impressive' Go overboard, be your own cheerleader.
Wiggle your toes...my god it helps. Especially in very early moments of attacks. Wiggle away. Better if you can try to do some sort of pattern pp because I find it is impossible and so I become amused that I have uncoordinated toes...
Anti depressants with help over time. The diazepam with also help, even if it doesn't seem to be.
Look, panic attacks are fucking horrid but they your body's best attempt to protect you. That pretty sweet of it. You have to help it see that there are other ways to cope. So if you can handle the slight cringe factor, then talk to yourself. ' Hello self, thanks for noticing that we might be in danger. It's not as scary as it looks so can we try another approach today? Let's enjoy the new experience at work. Etc...' do it with the same kindness you would so for a child in your care. Say 'well done' to yourself at every opportunity.
Sorry for the length. Hope these things help