Obviously different things help different people at different times, but some of the things (or perhaps a mixture of all of them plus time) that helped me are as follows -
f you're feeling very anxious and panicky try some of the calm breathing apps, the ones where it tells you to inhale and exhale for specific amounts of time.
Medication. Just because you've tried antidepressants and they have t worker, don't write them off - there are so many different ones and sometimes it's trial and error.
Talking therapies, although I know you said there are long waiting times. If this for the primary care depression and anxiety type NHS or more specific services? What are do you live in?
Even without talking therapies there are some really good self help books out there (or no doubt podcasts of you are struggling to concentrate enough to read)
Talking to someone who has been there and experienced it themselves and would listen just listen and be non judgemental. Realising that feeling this way is actually quite common can be quite powerful and remind you that you are not alone.
Taking it hour by hour and lowering the expectations you have of yourself. Celebrate the so called small things, which are absolutely not small when you are in the grips of depression, such as getting out of bed to have a shower.
Moving - for me walking and yoga helped.
ASMR - this is a bit of a personal one, but I find it hugely soothing.
You won't feel like this forever, keep going.