Changing Course in 1st year

I've finished my first year of medicine and I have hated it.
I am now considering applying for another degree whilst continuing medicine, just in case the application doesn't work out how I want it to. My question is, is it possible to apply for another course whilst attending uni, and if it is how I would submit my application.

Search for courses that are still open - UCAS Search https://digital.ucas.com/search
Enter a subject search word and on the next page use the filters (symbol up left) to narrow your search - make sure you also select 'courses still open' right at the bottom of the filter list.

This will show you what is still open - once you have 5 realistic choices, apply quickly.
You will need a new PS, and a reference - either your last school (phone them first and tell them what you are doing....) or a sympathetic tutor at your current Uni. Btw, be honest about why why are restarting with a new subject - its okay to change your mind - and make sure you include the 1 year of Med in your application.

What sort of subject do you want to go for?

I am looking for a computer science course