WCA afters years in ESA Support Group??

I was awoken with a text asking me to attend a Work Capability Assessment after years of being an ESA claimant in the support group. I had a total meltdown, it was so out of the blue and jarring. I spent most of today crying, shaking, being sick; all that fun anxiety stuff.

Short(ish) version:
- Suffered from depression/anxiety my whole life, diagnosed on multiple occasions. Both talk and CBT therapy didn't help. I take medication to help reduce symptoms a little.
- Lost my job in Dec 2013 after multiple absences/breakdowns at work.
- Been claiming ESA since Feb 2015 after an awful time on JSA.
- It is a JOINT claim; my partner has similar mental health issues, but only I complete the questionnaire every year. (I'm still not sure why)
- We moved house in May after our landlord got made redundant and needed the flat back, we live with my partner's family now as it's all we can afford.
- We informed the DWP that we moved via a letter but they didn't update their info apparently.
- The WCA WAS for next week and held where we used to live (which is 130 miles away!)
- Thankfully, my mum was able to call on my behalf today and change our address.
- Neither of us can communicate via a telephone, only text and a little in person, but that's very difficult for us too so a F2F assessment is terrifying.
- They told my mum that they'll set up a new WCA here on the 20th - but I honestly don't know if I can cope with attending, I really struggle with leaving the house at all now, let alone going somewhere I've never been before.


I was just wondering if anyone might know why only now I'm being asked to attend a WCA?

As I really struggle with going out (especially somewhere I don't know), do you think they'd be able to do a home visit instead? Is that something people have successfully been able to do? How can this be done if it's possible?

Finally, just any help/advice with the WCA itself because honestly I'm struggling to deal with the suddenness of it and reading horror stories from people who've been through them hasn't helped, it just feels so utterly pointless. I feel like no matter how much I'm able to explain my problems or how visible they are, they're just going to give me a 0 anyway and we're going to lose our only source of money and it will be all my fault for messing up during the assessment.
I mean, I've long stopped caring about my own well-being, but I'm concerned for my partner as a result of losing the money. Any help/advice is greatly appreciated! Thank you