I think CBT could really help you manage your feelings.
There is no need to be terrified. You have been trained into heightened anxiety by your dick of a partner.
You have a job. Now make an organised list of all the things you need to do step by step to make it possible to get there etc. Eg un-SORNing the car - lost out what you need to do, who to call etc.
Make a timetable for yourself so you can clearly see when you will do things.
Make a business plan for your business and break it down into a 3 month, 6 month and 12 month target. What needs to be done, by when, with whom?
Finally DO NOT show or discuss ANY of the above with your partner. He doesn’t need to know. He isn’t doing the work himself and he is unlikely to help you. He is NOT on your side. He is not your ally or your friend. He is your saboteur.
Then, when you feel terrified, look again at your timetable and just do the next thing on it. Look at your list of tasks and pick something achievable.
There is nothing to be terrified of. There will be times ahead that feel scary, like your first day at work or when you decide to get on that plane with or hopefully without your partner to see your mum. But they all just need one foot in front of the other to get through them.
And, most importantly, the less you tell your partner, the less likely you will be scared, because he won’t be undermining you or putting obstacles in your way to deliberately exhaust and frustrate you.
Finally finally, there are a lot of small business loans swilling about because of Covid. If your business is workable, part of your time spent working on it each week should be focused on raising capital through proper small business loans. Once again, never, ever touch your pension.